@saghul , is there some reason for this not being implemented? If you want, I can send a PR, something along these lines:

```c
int uv_stream_set_blocking(uv_stream_t* handle, int blocking) {
  int fd = handle->io_watcher.fd, rv;

  if (blocking) {
    rv = fcntl(fd, F_SETFL, fcntl(fd, F_GETFL, 0) & ~O_NONBLOCK);
  } else {
    rv = fcntl(fd, F_SETFL, fcntl(fd, F_GETFL, 0) | O_NONBLOCK);
  }

  return rv;
}
```

What do you say?