XDROutPacketAddDynamic
return XDROutPacketAddDynamic(packet, string, strlen(string));
status_t XDROutPacketAddDynamic (struct XDROutPacket *packet, const void *data, size_t size);
status_t err = XDROutPacketAddDynamic(&call, (const char *)buf + bytesWritten, count);
XDROutPacketAddDynamic (&rpc_call, NULL, 0);
XDROutPacketAddDynamic (&rpc_call, NULL, 0);