Webgl cache warming up can cause GC/slow app start up

[Tyriar]

[jerch]

Would it be possible to move some of the work to idle times with requestIdleCallback()?

[Tyriar]

@jerch great idea 👍! This is just warming up to avoid latency when rendering likely glyphs in the future so it can be deferred until after the initial render which would then only draw the minimal amount of glyphs in the viewport.

[Tyriar]

This is pretty much fixed in https://github.com/xtermjs/xterm.js/pull/4131