Output stream isn't written to with default param

[imjoshin]

The output stream isn't written to when using the default param. I originally thought it was an issue with using STDOUT in a non-CLI environment, but after implementing a similar fix to #48, I wasn't seeing any changes.

I added some of our logging into the send() method to see what's going on:

protected function send($data)
{
    if ($this->need_headers)
    {
        $this->send_http_headers();
    }

    \Log::message("Output stream is valid: " . (fstat($this->output_stream) !== false ? 'true' : 'false'));
    \Log::message("Writing " . strlen($data) . " bytes");

    $this->need_headers = false;

    do
    {
        $result = fwrite($this->output_stream, $data);
        \Log::message("Wrote $result bytes");
        $data = substr($data, $result);
        fflush($this->output_stream);
    } while ($data && $result !== false);
}

I received these logs:

Output stream is valid: true
Writing 4096 bytes
Wrote 4096 bytes
Output stream is valid: true
Writing 1084 bytes
Wrote 1084 bytes
Output stream is valid: true
Writing 452 bytes
Wrote 452 bytes

Unfortunately, the tar downloaded was 0 bytes.