[WFCORE-112] This removes the deadlock that is happening due
to a network failure during closeAsync call.
The close async was doing this:
1) send close (endpoint A)
2) receive close (endpoint B)
3) send close (endpoint B)
4) receive close (endpoint A) -> close the channel
If the network fails point 2 never takes place, then endpoint A waits
forever. It is changed to:
1) send close (endpoint A) -> close the channel
2) receive close (endpoint B) -> close the channel