Why doesn't gulp-if divert to branches as I'd expect?

Question

I'm having basic problems with gulp-if.

From the documentation I understand, that if condition is true, execute first part and (optionally) if not, then execute 2nd part. So I wrote this gulpfile.js. But it is absolutly not doing what I would have expected.

How can I divert the flow in a gulp pipe using gulp-if, depending on a condition?

const gulp = require('gulp'),
      log = require('fancy-log'),
      gulpif = require('gulp-if');

async function trueAction() {
    log('true')
}

async function falseAction() {
    log('false')
}

var condition = true;

gulp.task('test0', async function() {
    gulpif(condition, trueAction)
}); // output: nothing

gulp.task('test1', async function() {
    gulpif(condition, trueAction, falseAction)
}); // output: nothing

gulp.task('test2', async function() {
    gulpif(condition, trueAction())
}); // output: 'true'

gulp.task('test3', async function() {
    gulpif(condition, trueAction(), falseAction())
}); // output: 'true' AND 'false'

gulp.task('test4', async function() {
    gulpif(condition, log('here'))
});// output: 'Error: gulp-if: child action is required'