Example of keyboard dashing behaviour for Unity3D using TLPLib Reactive Extensions (https://github.com/tinylabproductions/tlplib)

gistfile1.cs

using System;
using System.Collections;
using com.tinylabproductions.TLPLib.Collection;
using com.tinylabproductions.TLPLib.Functional;
using com.tinylabproductions.TLPLib.Reactive;
using UnityEngine;

namespace Keyboard {
  class KeyboardDash : MonoBehaviour {
    private const int presses = 2;

    public float magnitude, dragCoeficient, timeframeSec, cooldownSec;
    public Space movementSpace = Space.World;

    internal void Start() {
      var up = 
        doublePress(KeyCode.W).join(doublePress(KeyCode.UpArrow)).
        map(_ => new Vector3(0, magnitude));

      var down = 
        doublePress(KeyCode.S).join(doublePress(KeyCode.DownArrow)).
        map(_ => new Vector3(0, -magnitude));

      var left = 
        doublePress(KeyCode.A).join(doublePress(KeyCode.LeftArrow)).
        map(_ => new Vector3(-magnitude, 0));

      var right = 
        doublePress(KeyCode.D).join(doublePress(KeyCode.RightArrow)).
        map(_ => new Vector3(magnitude, 0));

      var dashObs = up.join(down).join(left).join(right).onceEvery(cooldownSec);
      dashObs.subscribe(v => StartCoroutine(dash(v)));
    }

    private IEnumerator dash(Vector3 direction) {
      while (direction.magnitude > 0.0001) {
        transform.Translate(direction * Time.deltaTime, movementSpace);
        direction *= dragCoeficient;
        yield return null;
      }
    }

    private IObservable<ILinkedList<Tpl<Unit, float>>> 
    doublePress(KeyCode key) {
      return Observable.everyFrame.filter(_ => Input.GetKeyDown(key)).
        withinTimeframe(presses, timeframeSec);
    }
  }
}