int getSendBufferSize() {
    int result = sendBufferSize;
    if (result != -1) {
      return result;
    }
    try {
      result = getSocket().getSendBufferSize();
    } catch (SocketException ignore) {
      // just return a default
      result = owner.getConduit().tcpBufferSize;
    }
    sendBufferSize = result;
    return result;
  }
Returns the size of the send buffer on this connection's socket.
geode-core/src/main/java/org/apache/geode/internal/tcp/Connection.java