transition local state to CLOSED
free the endpoint and any associated resources
@return the local endpoint error, or null if there is none
@see #setContext(Object)
@return the local endpoint state
@return the remote endpoint error, or null if there is none
@return the remote endpoint state (as last communicated)
transition local state to ACTIVE
Set the local error condition @param condition
Sets an arbitrary an application owned object on the end-point. This object is not used by Proton.