Issue title: Set size limit for disk cache
 Issue body: Is it possible to do this at the moment? I looked through the APIs and didn't see anything right away. If not, could you possibly add an option to adjust it?

I see that I can turn off the disk cache altogether, but it would also be nice to be able to set the max cache size to be smaller than 1GB, since this is a lot of space on smaller devices.
 Comments: 
 Comment 0: You can use `Config.cacheSizeLimitInMegabytes`.
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