Unbounded internal cache sizes can lead to unbounded RAM use

[dweymouth]

Checklist

• I have searched the issue tracker for open issues that relate to the same problem, before opening a new one.
• This issue only relates to a single bug. I will open new issues for any other problems.

Describe the bug

Internal caches are currently unlimited in size, and are cleaned out on a fixed 1-minute schedule. This means that within a minute, apps can grow in RAM use unboundedly, possibly leading to out of memory errors, if they create a huge number of cached objects (especially text textures) within that time. For example, scrolling quickly through 10s of thousands of text-heavy list rows (which could contain on the order of 10 canvas.Texts each).

Possible ideas are to take inspiration from the Go GC itself - run our clean tasks more frequently based on use patterns, and have a "soft limit" on cache size which is based on the past patterns of use.

How to reproduce

scroll through many many rows of a text-heavy collection widget (eg extend the list or table in fyne_demo to be a million rows long)

Screenshots

No response

Example code

fyne_demo

Fyne version

develop

Go compiler version

n/a

Operating system and version

n/a

Additional Information

No response