docs: def subprocess_manager(self, exec_args):
          ''' Bro subprocess manager '''
          try:
              sp = gevent.subprocess.Popen(exec_args, stdout=gevent.subprocess.PIPE, stderr=gevent.subprocess.PIPE)
          except OSError:
              raise RuntimeError('Could not run bro executable (either not installed or not in path): %s' % (exec_args))
          out, err = sp.communicate()
          if out:
              print 'standard output of subprocess: %s' % out
          if err:
              raise RuntimeError('%s\npcap_bro had output on stderr: %s' % (exec_args, err))
          if sp.returncode:
              raise RuntimeError('%s\npcap_bro had returncode: %d' % (exec_args, sp.returncode))