There is a memory leak problem in wmsExtension

[RS-Y]

When I use the titiller application, I add the wmsExtension of the cog.Then I found that the memory used by uvicorn kept increasing and would not be released：

[vincentsarago]

Dear @RS-Y

We know there is something going on but we've been unable to really put a finger about where exactly it is.

But if you have reproducible example to share or more info please you're more than welcome

I'm going to close this issue but feel free to continue the thread over cogeotiff/rio-tiler#713