Cancellable data/tile loading

[maxammann]

maplibre-rs should be able to cancel data or tile requests after starting them.

🤔 Expected Behavior

If the user scrolls into some area then the tiles get loaded. If the user navigates away then pending requests should be cancelled.

😯 Current Behavior

Currently we have kind a work queue, which gets processed in the order of submission. No cancellation possible.

💁 Possible Solution

There are two major parts in order to support cancellation for tiles:

• Cancellable tessellation (~200ms)
• Cancellable tile fetching (~100ms, but depends on connection speed)

🔦 Context

• On web this is relevant: https://developer.mozilla.org/en-US/docs/Web/API/AbortController
• On non-web targets we are currently using reqwest which hopefully support abortion/cancellation.

We might switch to reqwest for the web target if it supports cancellation on all platforms.

💻 Examples

Does not apply.