code: func (m *monitor) Collect(in chan<- prometheus.Metric) {
  	// Gauge
  	m.connections.Collect(in)
  	m.requests.Collect(in)
  
  	// HistogramVec
  	m.requestDuration.Collect(in)
  
  	// CounterVec
  	m.requestsTotal.Collect(in)
  	m.messagesReceived.Collect(in)
  	m.messagesSend.Collect(in)
  	m.errors.Collect(in)
  }
docs: // Collect implements prometheus Collector interface.