message: ftp: Set size in message on read
diff: #endif
  #include <fcntl.h>
  #include <sys/stat.h>
  +#include <algorithm>
  #include "crc32.h"
  #include "fs.h"
  @@ -380,7 +381,8 @@ void FtpImpl::_read()
  payload->session = _session;
  payload->opcode = _curr_op = CMD_READ_FILE;
  payload->offset = _bytes_transferred;
  - payload->size = 0;
  + payload->size =
  + std::min(static_cast<uint32_t>(max_data_length), _file_size - _bytes_transferred);
  _send_mavlink_ftp_message(raw_payload);
  }
  