private void startDirectChannel(final MemberIdentifier memberID) {
    int dcPort = 0;

    if (!tcpDisabled) {
      directChannel = new DirectChannel(membership, dcReceiver, clusterDistributionManager);
      dcPort = directChannel.getPort();
    }
    memberID.setDirectChannelPort(dcPort);
  }
for mock testing this allows insertion of a DirectChannel mock
geode-core/src/main/java/org/apache/geode/distributed/internal/DistributionImpl.java