private void fail(Channel ch, Throwable error) {
          IOException ex = toIOE(error);
          LOG.warn("Exception encountered while connecting to the server " + remoteId.getAddress(),
            ex);
          if (connectionRegistryCall != null) {
            connectionRegistryCall.setException(ex);
          }
          failInit(ch, ex);
        }
RPC connection implementation based on netty.
<p/>
Most operations are executed in handlers. Netty handler is always executed in the same
thread(EventLoop) so no lock is needed.
<p/>
<strong>Implementation assumptions:</strong> All the private methods should be called in the
{@link #eventLoop} thread, otherwise there will be races.
@since 2.0.0
hbase-client/src/main/java/org/apache/hadoop/hbase/ipc/NettyRpcConnection.java