@Override
  public boolean checkIfAvailable(ID mbr, String reason,
      boolean initiateRemoval, boolean assumeMembersInFinalCheckAreAvailable) {
    if (assumeMembersInFinalCheckAreAvailable && membersInFinalCheck.contains(mbr)) {
      return true; // status unknown for now but someone is checking
    }
    return inlineCheckIfAvailable(localAddress, currentView, initiateRemoval,
        mbr, reason);
  }
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