Fixes: timer resource leak where it can be garbage collected only aft…

…er it fires

ethmonitor/ethmonitor.go

@@ -334,7 +334,6 @@ func (m *Monitor) listenNewHead() <-chan uint64 {
 				goto reconnect
 			}
 
-			blockTimer := time.NewTimer(3 * m.options.ExpectedBlockInterval)
 			for {
 				select {
 				case <-m.ctx.Done():
@@ -352,7 +351,7 @@ func (m *Monitor) listenNewHead() <-chan uint64 {
 					streamingErrorLastTime = time.Now()
 					goto reconnect
 
-				case <-blockTimer.C:
+				case <-time.After(3 * m.options.ExpectedBlockInterval):
 					// if we haven't received a new block in a while, we'll reconnect.
 					m.log.Warnf("ethmonitor: haven't received block in expected time, reconnecting..")
 					sub.Unsubscribe()
@@ -361,8 +360,6 @@ func (m *Monitor) listenNewHead() <-chan uint64 {
 					goto reconnect
 
 				case newHead := <-newHeads:
-					blockTimer.Reset(3 * m.options.ExpectedBlockInterval)
-
 					latestHeadBlock.Store(newHead.Number.Uint64())
 					select {
 					case nextBlock <- newHead.Number.Uint64():
@@ -395,6 +392,7 @@ func (m *Monitor) listenNewHead() <-chan uint64 {
 				case <-m.ctx.Done():
 					// if we're done, we'll close the nextBlock channel
 					close(nextBlock)
+					retryStreamingTimer.Stop()
 					return
 
 				case <-time.After(time.Duration(m.pollInterval.Load())):