Remove timestamp delta allowance and use reference timestamps in check

Glucose events can be out of order (and are frequently). Checking for
only reference timestamps should catch all relevant events.

RileyLinkKit/PumpOpsSynchronous.swift

@@ -552,9 +552,6 @@ class PumpOpsSynchronous {
 
         var events = [TimestampedGlucoseEvent]()
 
-        // Going to scan backwards in time through events, so event time should be monotonically decreasing.
-        let eventTimestampDeltaAllowance = TimeInterval(hours: 9)
-
         let currentGlucosePage = try readCurrentGlucosePage()
         let startPage = Int(currentGlucosePage.pageNum)
         let endPage = max(startPage - 1, 0)
@@ -589,8 +586,8 @@ class PumpOpsSynchronous {
                 timestamp.timeZone = pump.timeZone
 
                 if let date = timestamp.date {
-                    if date.timeIntervalSince(startDate) < -eventTimestampDeltaAllowance {
-                        NSLog("Found event at (%@) to be more than %@s before startDate(%@)", date as NSDate, String(describing: eventTimestampDeltaAllowance), startDate as NSDate);
+                    if date < startDate && event is ReferenceTimestampedGlucoseEvent {
+                        NSLog("Found reference event at (%@) to be before startDate(%@)", date as NSDate, startDate as NSDate);
                         break pages
                     } else {
                         events.insert(TimestampedGlucoseEvent(glucoseEvent: event, date: date), at: 0)