title: child_process.execFile() without buffering
body: <p>I'm using Node's <code>child_process.execFile()</code> to start and communicate with a process that puts all of its output into its standard output and error streams. The process runs for an indeterminate amount of time and may theoretically generate any amount of output, i.e.:</p>
  
  <pre><code>const process = execFile('path/to/executable', [], {encoding: buffer'});
  process.stdout.on('data', (chunk) =&gt; {
      doSomethingWith(chunk);
  });
  process.stderr.on('data', (chunk) =&gt; {
      renderLogMessage(chunk);
  });
  </code></pre>
  
  <p>Notice that I'm not using the last argument to <code>execFile()</code> because I never need an aggregated view of all data that ever came out of either of those streams. Despite this omission, Node appears to be buffering the output anyway and I can reliably make the process end with the <code>SIGTERM</code> signal just by giving it enough input for it to generate a large amount of output. That is problematic because the process is stateful and cannot simply be restarted periodically.</p>
  
  <p>How can I alter or work around this behavior?</p>