code: func (sdk *FabricSDK) initMetrics(configs *configs) {
  	if configs == nil {
  		return
  	}
  	if sdk.system == nil {
  		sdk.system = newOperationsSystem(configs)
  
  		err := sdk.system.Start()
  		if err != nil {
  			panic("metrics failed to start: " + err.Error())
  		}
  
  		// for now NewClientMetrics supports channel client. TODO: if other client types require metrics tracking, update this function
  		sdk.clientMetrics = metrics.NewClientMetrics(sdk.system.Provider)
  	}
  }
docs: // initMetrics will initialize the Go SDK's metric's system instance to allow capturing metrics data by the SDK clients.