Error captures the code and reason a channel or connection has been closed by the server.
// Channel and Connection exceptions will be broadcast on these listeners. closes chan *Error // Listeners for active=true flow control. When true is sent to a listener,
// Selects on any errors from shutdown during RPC errors chan *Error // State machine that manages frame order, must only be mutated by the connection
recv: (*Channel).recvMethod, send: (*Channel).sendOpen, errors: make(chan *Error, 1), } }