add WithMaxSendQueueSize function to configuration the send span queue buffer length (#61)

reporter/grpc.go

@@ -78,6 +78,13 @@ func WithCheckInterval(interval time.Duration) GRPCReporterOption {
 	}
 }
 
+// WithMaxSendQueueSize setup send span queue buffer length
+func WithMaxSendQueueSize(maxSendQueueSize int) GRPCReporterOption {
+	return func(r *gRPCReporter) {
+		r.sendCh = make(chan *agentv3.SegmentObject, maxSendQueueSize)
+	}
+}
+
 // WithInstanceProps setup service instance properties eg: org=SkyAPM
 func WithInstanceProps(props map[string]string) GRPCReporterOption {
 	return func(r *gRPCReporter) {

reporter/grpc_test.go

@@ -143,6 +143,15 @@ func TestGRPCReporterOption(t *testing.T) {
 				}
 			},
 		},
+		{
+			name:   "with max send queue size",
+			option: WithMaxSendQueueSize(50000),
+			verifyFunc: func(t *testing.T, reporter *gRPCReporter) {
+				if cap(reporter.sendCh) != 50000 {
+					t.Error("error are not set WithMaxSendQueueSize")
+				}
+			},
+		},
 		{
 			name:   "with serviceInstance props",
 			option: WithInstanceProps(instanceProps),