docs: def read_postmaster_opts(self):
          """returns the list of option names/values from postgres.opts, Empty dict if read failed or no file"""
          result = {}
          try:
              with open(os.path.join(self._data_dir, 'postmaster.opts')) as f:
                  data = f.read()
                  for opt in data.split('" "'):
                      if '=' in opt and opt.startswith('--'):
                          name, val = opt.split('=', 1)
                          result[name.strip('-')] = val.rstrip('"\n')
          except IOError:
              logger.exception('Error when reading postmaster.opts')
          return result