Changes to address infamous issue #47 (issue 30 in owncloud/ios-app#237…

…) by trying to limit background NSURLSession usage to those times where a transfer's duration will likely exceed the app's background time:

- OCHTTP
	- addition of OCHTTPPipelineTaskMetrics to record performance metrics of
		- detailed times (using NSURLSessionTaskMetrics)
		- traffic (from NSURLSessionTask)
		- hostname + timestamp
	- OCHTTPPipelineTask gets new .metrics property to keep an associated OCHTTPPipelineTaskMetrics object
	- OCHTTPPipeline support for OCHTTPPipelineTaskMetrics
		- takes and keeps OCHTTPPipelineTaskMetrics internally
			- only records whose net transfer time exceeded a threshold (0.01 seconds atm)
			- only holds onto records for 10 minutes
		- can provide estimates on
			- how long a given HTTP request will take to complete before sending it
			- how confident it is about that estimate
- OCConnection
	- new method to estimate transfer times for requests
		- queries longLived and command pipelines under the hood and uses the estimate with the higher confidence
	- new method to provide a pipeline depending on estimated transfer time
		- will return the command pipeline (typically backed by a local NSURLSession) for requests that are likely to finish within 2 minutes
		- will return the longlived pipeline (typically backed by a background NSURLSession) for
			- requests that are estimated to take longer than 2 minutes
			- requests whose estimation has a confidence below 15%
			- requests where no estimate is available
	- uploads and downloads now dispatch their requests to different pipelines depending on estimated transfer time

ownCloudSDK.xcodeproj/project.pbxproj

@@ -198,6 +198,8 @@
 		DC594B1F21EFD7F900B882C4 /* BookmarkManagerTests.m in Sources */ = {isa = PBXBuildFile; fileRef = DC594B1E21EFD7F900B882C4 /* BookmarkManagerTests.m */; };
 		DC5A20312074E8890083DB7D /* CoreTests.m in Sources */ = {isa = PBXBuildFile; fileRef = DC5A20302074E8890083DB7D /* CoreTests.m */; };
 		DC5A794F21E5FAF20045BCAA /* OCConnection+Signals.m in Sources */ = {isa = PBXBuildFile; fileRef = DC5A794D21E5FAF20045BCAA /* OCConnection+Signals.m */; };
+		DC5AD95422665AC800277DB0 /* OCHTTPPipelineTaskMetrics.h in Headers */ = {isa = PBXBuildFile; fileRef = DC5AD95222665AC800277DB0 /* OCHTTPPipelineTaskMetrics.h */; settings = {ATTRIBUTES = (Public, ); }; };
+		DC5AD95522665AC800277DB0 /* OCHTTPPipelineTaskMetrics.m in Sources */ = {isa = PBXBuildFile; fileRef = DC5AD95322665AC800277DB0 /* OCHTTPPipelineTaskMetrics.m */; };
 		DC61E931221423D2002889D6 /* HTTPPipelineTests.m in Sources */ = {isa = PBXBuildFile; fileRef = DC61E930221423D2002889D6 /* HTTPPipelineTests.m */; };
 		DC62FD62211B11FD0034B628 /* OCItem+OCThumbnail.h in Headers */ = {isa = PBXBuildFile; fileRef = DC62FD60211B11FD0034B628 /* OCItem+OCThumbnail.h */; };
 		DC62FD63211B11FD0034B628 /* OCItem+OCThumbnail.m in Sources */ = {isa = PBXBuildFile; fileRef = DC62FD61211B11FD0034B628 /* OCItem+OCThumbnail.m */; };
@@ -769,6 +771,8 @@
 		DC5A20302074E8890083DB7D /* CoreTests.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = CoreTests.m; sourceTree = "<group>"; };
 		DC5A20322074F9020083DB7D /* Ocean.entitlements */ = {isa = PBXFileReference; lastKnownFileType = text.plist.entitlements; path = Ocean.entitlements; sourceTree = SOURCE_ROOT; };
 		DC5A794D21E5FAF20045BCAA /* OCConnection+Signals.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = "OCConnection+Signals.m"; sourceTree = "<group>"; };
+		DC5AD95222665AC800277DB0 /* OCHTTPPipelineTaskMetrics.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = OCHTTPPipelineTaskMetrics.h; sourceTree = "<group>"; };
+		DC5AD95322665AC800277DB0 /* OCHTTPPipelineTaskMetrics.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = OCHTTPPipelineTaskMetrics.m; sourceTree = "<group>"; };
 		DC61E930221423D2002889D6 /* HTTPPipelineTests.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = HTTPPipelineTests.m; sourceTree = "<group>"; };
 		DC62FD60211B11FD0034B628 /* OCItem+OCThumbnail.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = "OCItem+OCThumbnail.h"; sourceTree = "<group>"; };
 		DC62FD61211B11FD0034B628 /* OCItem+OCThumbnail.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = "OCItem+OCThumbnail.m"; sourceTree = "<group>"; };
@@ -1535,6 +1539,8 @@
 				DC4B116F220830F20062BCDD /* OCHTTPPipelineBackend.h */,
 				DCE48DD7220E1C7B00839E97 /* OCHTTPPipelineTaskCache.m */,
 				DCE48DD6220E1C7A00839E97 /* OCHTTPPipelineTaskCache.h */,
+				DC5AD95322665AC800277DB0 /* OCHTTPPipelineTaskMetrics.m */,
+				DC5AD95222665AC800277DB0 /* OCHTTPPipelineTaskMetrics.h */,
 			);
 			path = Pipeline;
 			sourceTree = "<group>";
@@ -2321,6 +2327,7 @@
 				DCC8FA0F2029C6A400EB6701 /* OCQueryChangeSet.h in Headers */,
 				DC701484220B090B009D4FD9 /* OCHTTPTypes.h in Headers */,
 				DC708CCE2141306100FE43CA /* OCSyncActionCopyMove.h in Headers */,
+				DC5AD95422665AC800277DB0 /* OCHTTPPipelineTaskMetrics.h in Headers */,
 				DCC8F9D9202854FB00EB6701 /* OCCore.h in Headers */,
 				DC4AFAB4206AE61400189B9A /* OCSQLiteQuery.h in Headers */,
 				DC4AFAA6206A6E7100189B9A /* OCSQLiteResultSet.h in Headers */,
@@ -2900,6 +2907,7 @@
 				DCADC0452072CCC900DB8E83 /* OCCoreItemListTask.m in Sources */,
 				DC576EC7226484E30087316D /* OCBackgroundManager.m in Sources */,
 				DCB0A46521B922A400FAC4E9 /* OCCoreConnectionStatusSignalProvider.m in Sources */,
+				DC5AD95522665AC800277DB0 /* OCHTTPPipelineTaskMetrics.m in Sources */,
 				DC708CE5214135E200FE43CA /* OCSyncActionDownload.m in Sources */,
 				DCEEB2E62044B0A400189B9A /* OCAuthenticationMethod+OCTools.m in Sources */,
 				DC139CC920DBB8440090175A /* OCChecksum.m in Sources */,

ownCloudSDK/Connection/OCConnection.m

@@ -1155,6 +1155,60 @@ - (void)_handleRetrieveItemListAtPathResult:(OCHTTPRequest *)request error:(NSEr
 	}
 }
 
+#pragma mark - Estimates
+- (NSNumber *)estimatedTimeForTransferRequest:(OCHTTPRequest *)request withExpectedResponseLength:(NSUInteger)expectedResponseLength confidence:(double * _Nullable)outConfidence
+{
+	double longlivedConfidence = 0;
+	NSNumber *longLivedEstimatedTime = [self.longLivedPipeline estimatedTimeForRequest:request withExpectedResponseLength:expectedResponseLength confidence:&longlivedConfidence];
+
+	double commandConfidence = 0;
+	NSNumber *commandEstimatedTime = [self.commandPipeline estimatedTimeForRequest:request withExpectedResponseLength:expectedResponseLength confidence:&commandConfidence];
+
+	double estimationConfidence = 0;
+	NSNumber *estimatedTime = nil;
+
+	if ((commandEstimatedTime != nil) && (commandConfidence > longlivedConfidence))
+	{
+		estimatedTime = commandEstimatedTime;
+		estimationConfidence = commandConfidence;
+	}
+	else if ((longLivedEstimatedTime != nil) && (longlivedConfidence > commandConfidence))
+	{
+		estimatedTime = longLivedEstimatedTime;
+		estimationConfidence = longlivedConfidence;
+	}
+
+	if (outConfidence != NULL)
+	{
+		*outConfidence = estimationConfidence;
+	}
+
+	return (estimatedTime);
+}
+
+- (OCHTTPPipeline *)transferPipelineForRequest:(OCHTTPRequest *)request withExpectedResponseLength:(NSUInteger)expectedResponseLength
+{
+	double confidenceLevel = 0;
+	NSNumber *estimatedTime = nil;
+
+	if (!OCProcessManager.isProcessExtension)
+	{
+		if ((estimatedTime = [self estimatedTimeForTransferRequest:request withExpectedResponseLength:expectedResponseLength confidence:&confidenceLevel]) != nil)
+		{
+			BOOL useCommandPipeline = (estimatedTime.doubleValue <= 120.0) && (confidenceLevel >= 0.15);
+
+			OCLogDebug(@"Expected finish time: %@ (in %@ seconds, confidence %.02f) - pipeline: %@", [NSDate dateWithTimeIntervalSinceNow:estimatedTime.doubleValue], estimatedTime, confidenceLevel, (useCommandPipeline ? @"command" : @"longLived"));
+
+			if (useCommandPipeline)
+			{
+				return (self.commandPipeline);
+			}
+		}
+	}
+
+	return (self.longLivedPipeline);
+}
+
 #pragma mark - Actions
 
 #pragma mark - File transfer: upload
@@ -1285,7 +1339,7 @@ - (OCProgress *)uploadFileFromURL:(NSURL *)sourceURL withName:(NSString *)fileNa
 			request.requestObserver = options[OCConnectionOptionRequestObserverKey];
 		}
 
-		[self.longLivedPipeline enqueueRequest:request forPartitionID:self.partitionID];
+		[[self transferPipelineForRequest:request withExpectedResponseLength:1000] enqueueRequest:request forPartitionID:self.partitionID];
 
 		requestProgress = request.progress;
 		requestProgress.progress.eventType = OCEventTypeUpload;
@@ -1434,7 +1488,7 @@ - (OCProgress *)downloadItem:(OCItem *)item to:(NSURL *)targetURL options:(NSDic
 		[self attachToPipelines];
 
 		// Enqueue request
-		[self.longLivedPipeline enqueueRequest:request forPartitionID:self.partitionID];
+		[[self transferPipelineForRequest:request withExpectedResponseLength:item.size] enqueueRequest:request forPartitionID:self.partitionID];
 
 		requestProgress = request.progress;
 		requestProgress.progress.eventType = OCEventTypeDownload;

ownCloudSDK/HTTP/Pipeline/OCHTTPPipeline.h

@@ -156,6 +156,9 @@ NS_ASSUME_NONNULL_BEGIN
 #pragma mark - Progress
 - (nullable NSProgress *)progressForRequestID:(OCHTTPRequestID)requestID;
 
+#pragma mark - Metrics
+- (nullable NSNumber *)estimatedTimeForRequest:(OCHTTPRequest *)request withExpectedResponseLength:(NSUInteger)expectedResponseLength confidence:(double * _Nullable)outConfidence;//!< If a sufficient amount of metrics could be collected, returns the estimated number of seconds it'll take the request to be sent and a response of expectedResponseLength be received.
+
 #pragma mark - Internal job queue
 - (void)queueBlock:(dispatch_block_t)block withBusy:(BOOL)withBusy; //!< Add a block for execution on the internal job queue.
 

ownCloudSDK/HTTP/Pipeline/OCHTTPPipeline.m

@@ -42,6 +42,10 @@ @interface OCHTTPPipeline ()
 	NSMutableSet<OCHTTPPipelinePartitionID> *_partitionsInDestruction;
 	NSMutableDictionary<OCHTTPPipelinePartitionID, NSMutableArray<dispatch_block_t> *> *_partitionEmptyHandlers;
 
+	NSMutableArray<OCHTTPPipelineTaskMetrics *> *_metricsHistory;
+	NSTimeInterval _metricsHistoryMaxAge;
+	NSTimeInterval _metricsMinimumTotalTransferDurationRelevancyThreshold;
+
 	dispatch_group_t _busyGroup;
 }
 
@@ -68,6 +72,10 @@ - (instancetype)initWithIdentifier:(OCHTTPPipelineID)identifier backend:(nullabl
 		_sessionCompletionHandlersByIdentifiers = [NSMutableDictionary new];
 		_partitionsInDestruction = [NSMutableSet new];
 
+		_metricsHistory = [NSMutableArray new];
+		_metricsHistoryMaxAge = 10 * 60; //!< Metrics records are used for computation for a maximum of 10 minutes
+		_metricsMinimumTotalTransferDurationRelevancyThreshold = 0.01; // Only metrics with a minimum total transfer duration of X secs should be considered relevant
+
 		_busyGroup = dispatch_group_create();
 
 		// Set backend
@@ -1617,6 +1625,8 @@ - (void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)urlSessionTa
 	{
 		OCLogDebug(@"Known task [taskIdentifier=<%lu>, url=%@] didCompleteWithError=%@", urlSessionTask.taskIdentifier, OCLogPrivate(urlSessionTask.currentRequest.URL),  error);
 
+		[self addMetrics:task.metrics withTask:urlSessionTask];
+
 		if (error != nil)
 		{
 			OCHTTPResponse *response = [task responseFromURLSessionTask:urlSessionTask];
@@ -1644,13 +1654,21 @@ - (void)URLSession:(NSURLSession *)session taskIsWaitingForConnectivity:(NSURLSe
 
 -(void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)urlSessionTask didFinishCollectingMetrics:(NSURLSessionTaskMetrics *)metrics
 {
+	OCHTTPPipelineTask *task = nil;
+	NSError *backendError = nil;
+
 	if (OCLogger.logLevel <= OCLogLevelDebug)
 	{
 		NSString *XRequestID = [urlSessionTask.currentRequest.allHTTPHeaderFields objectForKey:@"X-Request-ID"];
 		NSArray <OCLogTagName> *extraTags = [NSArray arrayWithObjects: @"HTTP", @"Metrics", urlSessionTask.currentRequest.HTTPMethod, OCLogTagTypedID(@"RequestID", XRequestID), OCLogTagTypedID(@"URLSessionTaskID", @(urlSessionTask.taskIdentifier)), nil];
 
 		OCPLogDebug(OCLogOptionLogRequestsAndResponses, extraTags, @"Task [taskIdentifier=<%lu>, url=%@] didFinishCollectingMetrics: %@", urlSessionTask.taskIdentifier, OCLogPrivate(urlSessionTask.currentRequest.URL), [metrics compactSummaryWithTask:urlSessionTask]);
 	}
+
+	if ((task = [self.backend retrieveTaskForPipeline:self URLSession:session task:urlSessionTask error:&backendError]) != nil)
+	{
+		task.metrics = [[OCHTTPPipelineTaskMetrics alloc] initWithURLSessionTaskMetrics:metrics];
+	}
 }
 
 - (void)URLSession:(NSURLSession *)session
@@ -1894,6 +1912,172 @@ - (void)URLSession:(NSURLSession *)session downloadTask:(NSURLSessionDownloadTas
 	// OCLogDebug(@"DOWNLOADTASK FINISHED: %@ %@ %@", downloadTask, location, request);
 }
 
+#pragma mark - Metrics
+- (void)addMetrics:(OCHTTPPipelineTaskMetrics *)metrics withTask:(NSURLSessionTask *)task
+{
+	if ((metrics != nil) && (task != nil))
+	{
+		if ((metrics.totalTransferDuration.doubleValue > _metricsMinimumTotalTransferDurationRelevancyThreshold) &&
+		    ((-[metrics.date timeIntervalSinceNow]) < _metricsHistoryMaxAge))
+		{
+			[metrics addTransferSizesFromURLSessionTask:task];
+
+			@synchronized(_metricsHistory)
+			{
+				// Drop outdated records
+				[_metricsHistory filterUsingPredicate:[NSPredicate predicateWithBlock:^BOOL(OCHTTPPipelineTaskMetrics *filterMetrics, NSDictionary<NSString *,id> * _Nullable bindings) {
+					return ((-[filterMetrics.date timeIntervalSinceNow]) < self->_metricsHistoryMaxAge);
+				}]];
+
+				// Add new record
+				[_metricsHistory addObject:metrics];
+			}
+		}
+	}
+}
+
+- (BOOL)weightedAverageSendBytesPerSecond:(NSNumber **)outSendBytesPerSecond receiveBytesPerSecond:(NSNumber **)outReceiveBytesPerSecond transportationDelaySeconds:(NSNumber **)outTransportationDelaySeconds largestSendBytes:(NSUInteger *)outLargestSendBytes largestReceiveBytes:(NSUInteger *)outLargestReceiveBytes forHostname:(NSString *)hostname
+{
+	@synchronized(_metricsHistory)
+	{
+		NSUInteger totalSendBytesPerSecond = 0;
+		NSUInteger totalSendBytesPerSecondSamples = 0;
+
+		NSUInteger totalReceiveBytesPerSecond = 0;
+		NSUInteger totalReceiveBytesPerSecondSamples = 0;
+
+		NSTimeInterval totalTransportationDelaySeconds = 0;
+		NSUInteger     totalTransportationDelaySamples = 0;
+
+		NSUInteger totalSentBytes = 0;
+		NSUInteger totalReceivedBytes = 0;
+
+		NSUInteger largestSentBytes = 0;
+		NSUInteger largestReceiveBytes = 0;
+
+		for (OCHTTPPipelineTaskMetrics *metrics in _metricsHistory)
+		{
+			if (((-[metrics.date timeIntervalSinceNow]) < _metricsHistoryMaxAge) && [metrics.hostname isEqual:hostname])
+			{
+				NSNumber *number;
+
+				if ((number = metrics.sentBytesPerSecond) != nil)
+				{
+					NSUInteger totalBytes = metrics.totalRequestSizeBytes.unsignedIntegerValue;
+
+					totalSendBytesPerSecond += number.unsignedIntegerValue * totalBytes;
+					totalSendBytesPerSecondSamples += 1;
+
+					totalSentBytes += totalBytes;
+
+					if (largestSentBytes < totalBytes)
+					{
+						largestSentBytes = totalBytes;
+					}
+				}
+
+				if ((number = metrics.receivedBytesPerSecond) != nil)
+				{
+					NSUInteger totalBytes = metrics.totalResponseSizeBytes.unsignedIntegerValue;
+
+					totalReceiveBytesPerSecond += number.unsignedIntegerValue * totalBytes;
+					totalReceiveBytesPerSecondSamples += 1;
+
+					totalReceivedBytes += metrics.totalResponseSizeBytes.unsignedIntegerValue;
+
+					if (largestReceiveBytes < totalBytes)
+					{
+						largestReceiveBytes = totalBytes;
+					}
+				}
+
+				if ((number = metrics.serverProcessingTimeInterval) != nil)
+				{
+					totalTransportationDelaySeconds += number.doubleValue;
+					totalTransportationDelaySamples += 1;
+				}
+			}
+		}
+
+		if ((totalSendBytesPerSecondSamples > 0) && (totalSentBytes > 0))
+		{
+			*outSendBytesPerSecond = @(totalSendBytesPerSecond / (totalSentBytes * totalSendBytesPerSecondSamples));
+		}
+		else
+		{
+			*outSendBytesPerSecond = nil;
+		}
+
+		if ((totalReceiveBytesPerSecondSamples > 0) && (totalReceivedBytes > 0))
+		{
+			*outReceiveBytesPerSecond = @(totalReceiveBytesPerSecond / (totalReceivedBytes * totalReceiveBytesPerSecondSamples));
+		}
+		else
+		{
+			*outReceiveBytesPerSecond = nil;
+		}
+
+		if (totalTransportationDelaySamples > 0)
+		{
+			*outTransportationDelaySeconds = @(totalTransportationDelaySeconds / ((NSTimeInterval)totalTransportationDelaySamples));
+		}
+		else
+		{
+			*outTransportationDelaySeconds = nil;
+		}
+
+		*outLargestReceiveBytes = largestReceiveBytes;
+		*outLargestSendBytes = largestSentBytes;
+
+		return ((totalSendBytesPerSecondSamples > 0) && (totalReceiveBytesPerSecondSamples > 0) && (totalTransportationDelaySeconds > 0));
+	}
+}
+
+- (nullable NSNumber *)estimatedTimeForRequest:(OCHTTPRequest *)request withExpectedResponseLength:(NSUInteger)expectedResponseLength confidence:(double *)outConfidence
+{
+	NSNumber *averageSendBytesPerSecond=nil, *averageReceiveBytesPerSecond=nil, *averageTransportationDelay = nil;
+	NSUInteger largestSendBytes = 0, largestReceivesBytes = 0;
+
+	if ([self weightedAverageSendBytesPerSecond:&averageSendBytesPerSecond receiveBytesPerSecond:&averageReceiveBytesPerSecond transportationDelaySeconds:&averageTransportationDelay largestSendBytes:&largestSendBytes largestReceiveBytes:&largestReceivesBytes	 forHostname:request.url.host])
+	{
+		NSUInteger requestSize = 0, responseSize = expectedResponseLength;
+		NSTimeInterval estimatedTimeToComplete = 0;
+		CGFloat confidenceLevel = 0;
+
+		[request prepareForScheduling];
+
+		requestSize += [OCHTTPPipelineTaskMetrics lengthOfHeaderDictionary:request.headerFields method:request.method url:request.effectiveURL];
+
+		if (request.bodyURL != nil)
+		{
+			NSNumber *fileSize = nil;
+
+			if ([request.bodyURL getResourceValue:&fileSize forKey:NSURLFileSizeKey error:NULL])
+			{
+				requestSize += fileSize.unsignedIntegerValue;
+			}
+		}
+		else
+		{
+			requestSize += request.bodyData.length;
+		}
+
+		estimatedTimeToComplete = ((NSTimeInterval)requestSize / (NSTimeInterval)averageSendBytesPerSecond.unsignedIntegerValue) + ((NSTimeInterval)responseSize / (NSTimeInterval)averageReceiveBytesPerSecond.unsignedIntegerValue) + averageTransportationDelay.doubleValue;
+
+		confidenceLevel = (CGFloat)1.0 / ((((CGFloat)(requestSize*requestSize) / (CGFloat)largestSendBytes) + ((CGFloat)(responseSize*responseSize) / (CGFloat)largestReceivesBytes)) / ((CGFloat)(requestSize + responseSize)));
+
+		OCLogDebug(@"weightedAverage sendBPS=%@, receiveBPS=%@, transportationDelay=%@ - bytesToSend=%lu, bytesToReceive=%lu - estimatedTimeToComplete=%.02f, confidenceLevel=%.03f", averageSendBytesPerSecond, averageReceiveBytesPerSecond, averageTransportationDelay, requestSize, responseSize, estimatedTimeToComplete, confidenceLevel);
+
+		if (outConfidence != NULL)
+		{
+			*outConfidence = confidenceLevel;
+		}
+
+		return (@(estimatedTimeToComplete));
+	}
+
+	return (nil);
+}
 
 #pragma mark - Progress
 - (nullable NSProgress *)progressForRequestID:(OCHTTPRequestID)requestID

ownCloudSDK/HTTP/Pipeline/OCHTTPPipelineTask.h

@@ -18,6 +18,7 @@
 
 #import <Foundation/Foundation.h>
 #import "OCHTTPPipeline.h"
+#import "OCHTTPPipelineTaskMetrics.h"
 
 NS_ASSUME_NONNULL_BEGIN
 
@@ -56,6 +57,8 @@ NS_ASSUME_NONNULL_BEGIN
 @property(nullable,strong,nonatomic) OCHTTPResponse *response;	//!< The response. Lazily deserializes .responseData as needed.
 @property(nullable,strong,nonatomic,readonly) NSData *responseData;	//!< The serialized response. Lazily serializes .response as needed.
 
+@property(nullable,strong) OCHTTPPipelineTaskMetrics *metrics; 	//!< (optional) metrics for the task (typically not serialized)
+
 @property(assign) BOOL finished; 				//!< The task has been finished
 
 #pragma mark - Init