whole_func_string: function idleRunner(runner_id, callback) {
              if (!runners[runner_id]) {
                  return callback(new e.BackendResourceNotFoundError(sprintf(
                    'Runner with uuid \'%s\' does not exist', runner_id)));
              } else {
                  runners[runner_id].idle = true;
                  return callback(null);
              }
          }
func_code_string: function idleRunner(runner_id, callback) {
              if (!runners[runner_id]) {
                  return callback(new e.BackendResourceNotFoundError(sprintf(
                    'Runner with uuid \'%s\' does not exist', runner_id)));
              } else {
                  runners[runner_id].idle = true;
                  return callback(null);
              }
          }
func_documentation_string: Set a runner as idle: - runner_id - String, unique identifier for runner - callback - f(err)