`TypeError` upon removing `VectorField` layer from map using layer control

[zacharyburnett]

When unchecking a VectorFieldAnim layer from a layer control, the console shows the following error several hundred times:

Uncaught TypeError: Cannot read property 'latLngToContainerPoint' of null
    at e._drawParticle (L.CanvasLayer.VectorFieldAnim.js:122)
    at L.CanvasLayer.VectorFieldAnim.js:109
    at Array.forEach (<anonymous>)
    at n (L.CanvasLayer.VectorFieldAnim.js:108)
    at L.CanvasLayer.VectorFieldAnim.js:52
    at Mn (d3.v4.min.js:2)
    at Tn (d3.v4.min.js:2)

Is some asynchronous particle calculation not stopping after removing the map?

[zacharyburnett]

I can reproduce this behavior with the following steps using a layer control:

1. Add the VectorFieldAnim layer

2. Add a ScalarField layer, in this case from an ASCII grid file

3. Remove the VectorFieldAnim layer

The errors stop when the VectorFieldAnim layer is put back into the map

[rmarzocchi84]

Perhaps related https://github.com/IHCantabria/Leaflet.CanvasLayer.Field/issues/41 (I have the same behaviour)