@Override
  public boolean checkIfAvailable(ID mbr, String reason,
      boolean initiateRemoval) {
    return checkIfAvailable(mbr, reason, initiateRemoval, true);
  }
During final check, establish TCP connection between current member and suspect member. And
exchange PING/PONG message to see if the suspect member is still alive.

@param suspectMember member that does not respond to HeartbeatRequestMessage
@return true if successfully exchanged PING/PONG with TCP connection, otherwise false.
geode-membership/src/main/java/org/apache/geode/distributed/internal/membership/gms/fd/GMSHealthMonitor.java