function spreadus() {
    var args = Array.prototype.slice.apply(arguments);
    args._spreadus_ = true;
    return args;
  }
function spreadus() {
    var args = Array.prototype.slice.apply(arguments);
    args._spreadus_ = true;
    return args;
  }
function spreadus ( ) { var args = Array . prototype . slice . apply ( arguments ) ; args . _spreadus_ = true ; return args ; }
For sliceThen(..).exec(proc, ..), mark what proc function returns is multiple values
to be passed to further Promise#spread(..) call.
For sliceThen ( .. ) . exec ( proc .. ) mark what proc function returns is multiple values to be passed to further Promise#spread ( .. ) call .