static int dm_sendFileToOtherMachine_chunkSize = 100*1024; // 1024*1024;

svoid dm_sendFileToOtherMachine(File f, S computerID, S remotePath) {
  dm_evalOnOtherMachine(computerID, "backupFile(fileRelativeToUserDirUnlessAbsolute(" + quote(remotePath) + "));");
  for (LongRange r : chunks(fileSize(f), dm_sendFileToOtherMachine_chunkSize)) {
    print("Sending file chunk " + r + " of " + f + " to " + computerID + ":" + remotePath);
    dm_evalOnOtherMachine(computerID, "saveBinaryFilePart_base64(fileRelativeToUserDirUnlessAbsolute(" + quote(remotePath) + "), " + r.start + "L, " + quote(base64encode(loadBinaryFileChunk(f, r))) + ");");
  }
  dm_evalOnOtherMachine(computerID, "truncateFile(fileRelativeToUserDirUnlessAbsolute(" + quote(remotePath) + ", " + fileSize(f) + "L));");
}

// works only for files under user dir. sends them to same path
// in remote user dir.
svoid dm_sendFileToOtherMachine(File f, S computerID) {
  S path = assertNotNull(f2s(f) + " is not in " + userDir(), pathRelativeToUserDir(f));
  dm_sendFileToOtherMachine(f, computerID, path);
}