Added Websocket's broadcast queue load metrics (#13935)

Now we send metrics when the websocket's broadcast queue receive or
consume a message from the queue

einterfaces/metrics.go

@@ -37,6 +37,8 @@ type MetricsInterface interface {
 
 	IncrementWebsocketEvent(eventType string)
 	IncrementWebSocketBroadcast(eventType string)
+	IncrementWebSocketBroadcastBufferSize(hub string, amount float64)
+	DecrementWebSocketBroadcastBufferSize(hub string, amount float64)
 
 	AddMemCacheHitCounter(cacheName string, amount float64)
 	AddMemCacheMissCounter(cacheName string, amount float64)

einterfaces/mocks/MetricsInterface.go

@@ -21,6 +21,11 @@ func (_m *MetricsInterface) AddMemCacheMissCounter(cacheName string, amount floa
 	_m.Called(cacheName, amount)
 }
 
+// DecrementWebSocketBroadcastBufferSize provides a mock function with given fields: hub, amount
+func (_m *MetricsInterface) DecrementWebSocketBroadcastBufferSize(hub string, amount float64) {
+	_m.Called(hub, amount)
+}
+
 // IncrementChannelIndexCounter provides a mock function with given fields:
 func (_m *MetricsInterface) IncrementChannelIndexCounter() {
 	_m.Called()
@@ -141,6 +146,11 @@ func (_m *MetricsInterface) IncrementWebSocketBroadcast(eventType string) {
 	_m.Called(eventType)
 }
 
+// IncrementWebSocketBroadcastBufferSize provides a mock function with given fields: hub, amount
+func (_m *MetricsInterface) IncrementWebSocketBroadcastBufferSize(hub string, amount float64) {
+	_m.Called(hub, amount)
+}
+
 // IncrementWebhookPost provides a mock function with given fields:
 func (_m *MetricsInterface) IncrementWebhookPost() {
 	_m.Called()