flush interval reader when stopping metric reader (#282)

* flush interval reader when stopping metric reader

fix staticcheck error

* fix staticcheck errors

go.mod

@@ -3,21 +3,22 @@ module contrib.go.opencensus.io/exporter/stackdriver
 go 1.12
 
 require (
-	cloud.google.com/go v0.45.1
-	github.com/aws/aws-sdk-go v1.23.20
-	github.com/census-instrumentation/opencensus-proto v0.2.1
-	github.com/golang/protobuf v1.3.2
-	github.com/google/go-cmp v0.3.1
-	github.com/jstemmer/go-junit-report v0.0.0-20190106144839-af01ea7f8024
-	go.opencensus.io v0.22.4
-	golang.org/x/lint v0.0.0-20190409202823-959b441ac422
-	golang.org/x/net v0.0.0-20190923162816-aa69164e4478
-	golang.org/x/oauth2 v0.0.0-20190604053449-0f29369cfe45
-	golang.org/x/sync v0.0.0-20190911185100-cd5d95a43a6e // indirect
-	golang.org/x/tools v0.0.0-20191010075000-0337d82405ff
-	google.golang.org/api v0.10.0
-	google.golang.org/appengine v1.6.2 // indirect
-	google.golang.org/genproto v0.0.0-20190911173649-1774047e7e51
-	google.golang.org/grpc v1.23.1
-	honnef.co/go/tools v0.0.1-2019.2.3
+	cloud.google.com/go v0.75.0
+	github.com/aws/aws-sdk-go v1.37.0
+	github.com/census-instrumentation/opencensus-proto v0.3.0
+	github.com/golang/protobuf v1.4.3
+	github.com/google/go-cmp v0.5.4
+	github.com/jstemmer/go-junit-report v0.9.1
+	go.opencensus.io v0.22.6
+	golang.org/x/lint v0.0.0-20201208152925-83fdc39ff7b5
+	golang.org/x/net v0.0.0-20210119194325-5f4716e94777
+	golang.org/x/oauth2 v0.0.0-20210126194326-f9ce19ea3013
+	golang.org/x/sys v0.0.0-20210124154548-22da62e12c0c // indirect
+	golang.org/x/text v0.3.5 // indirect
+	golang.org/x/tools v0.0.0-20210108195828-e2f9c7f1fc8e
+	google.golang.org/api v0.37.0
+	google.golang.org/genproto v0.0.0-20210126160654-44e461bb6506
+	google.golang.org/grpc v1.35.0
+	google.golang.org/protobuf v1.25.0
+	honnef.co/go/tools v0.0.1-2020.1.4
 )

internal/testpb/generate.sh

@@ -1,7 +1,7 @@
 #!/bin/sh
 # generate .pb.go file from .proto file.
 set -e
-protoc --go_out=plugins=grpc:. test.proto
+protoc --go_out=. --go-grpc_out=. test.proto
 echo '
 //go:generate ./generate.sh
 ' >> test.pb.go

internal/testpb/impl.go

@@ -62,6 +62,10 @@ func (s *testServer) Multiple(stream Foo_MultipleServer) error {
 	}
 }
 
+// mustEmbedUnimplementedFooServer is a dummy method added to satisfy
+// FooServer interface
+func (*testServer) mustEmbedUnimplementedFooServer() {}
+
 // NewTestClient is used for internal testing only. It creates a
 // grpc server and client. It returns client and cleanup function
 // to close the connection and gracefully stop the server.