Calling the codes in Background processing in PHP

  $check_async_calls_dashboard = variable_get('gems_dashboard_async_call', '0');
  if ($check_async_calls_dashboard) {
     // buffer all upcoming output
     @apache_setenv('no-gzip', 1);
     @ini_set('zlib.output_compression', 0);
     @ini_set('implicit_flush', 1);
     ignore_user_abort(true);
     set_time_limit(0);
     ob_start();
     echo 'done';
     // get the size of the output
     $size = ob_get_length();
     // send headers to tell the browser to close the connection
     header("Content-Length: $size");
     header('Connection: close');
     // flush all output
     ob_end_flush();
     ob_flush();
     flush();
     // close current session
     // if (session_id()) session_write_close();
  }

/* put your coding here.. which need to call in background process.. */