Ability to cancel tile requests (even after they start)

Target Use case

Improve performance when getTileData makes fetch requests that are slow. Browsers only allow so many concurrent fetch requests. If a user pans around enough fill up the max concurrent requests of the browser, then newer requests for what the user is actually seeing are queued behind requests for tiles that are now off the screen.

Proposed feature

Expose an AbortSignal instance to the getTileData function. If a tile’s request is “cancelled”, then its abort signal is triggered. This AbortSignal can be passed to the fetch options in order to cancel the fetch request if, for example, a tile never finished loading and is now off the screen.

To Do List

• Add label and assign to milestone
• Coding
• Doc update
• What’s new update
• Test

[kylebarron]

As part of the options passed to its fetch calls if the application passes data array with the x, y, z placeholders

Note that the data prop doesn’t call fetch on its own. The data prop only handles url resolution, and then passes to getTileData. So I think your argument 2 is to send an AbortSignal instance to the default getTileData, which is fetch: https://github.com/visgl/deck.gl/blob/1aff4952f5a5229abcd18e50af977c25eabee76a/modules/geo-layers/src/tile-layer/tile-layer.js#L139-L144

[supersonicclay]

The PR is now ready for review and works well I think.