class EventMachine::Synchrony::TCPSocket

def unbind(reason)

value.
EM fails to pass in the reason argument and you'll always get the default
Can't set a default value for reason (e.g. reason=nil), as in that case 
def unbind(reason)
  @unbind_reason = reason
  @remote_closed = true unless @closed
  if @opening
    @in_req.fail nil if @in_req
  else
    @in_req.succeed read_data if @in_req
  end
  @out_req.fail nil if @out_req
  @in_req = @out_req = nil
end