code: @SuppressFBWarnings("UPM_UNCALLED_PRIVATE_METHOD")
      private static void requestClose(long handle, int status, String message) {
          Log.w(LogDomain.NETWORK, "C4Socket.requestClose() handle -> " + handle);
          final C4Socket socket = REVERSE_LOOKUP_TABLE.get(handle);
          if (socket != null) { socket.requestClose(status, message); }
          else { Log.w(LogDomain.NETWORK, "socket is null"); }
      }
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