Rasterio only accepts GDAL_CACHEMAX as bytes

[fungjj92]

I've been diving into cache settings for my titiler instance and discovered some conflicting information;
Titiler docs explain GDAL_CACHEMAX can be in MB, bytes or percent.

While GDAL does accept MB, bytes or percent, titiler sets GDAL env variables via Rasterio. As I dug through the Rasterio project, I believe it only accepts bytes for GDAL_CACHEMAX

https://rasterio.readthedocs.io/en/latest/topics/switch.html#the-gdal-environment
rasterio/rasterio#2336
rasterio/rasterio#1042

[fungjj92]

Sorry if I misfiled; this is probably more of a candidate for an "issue" than a "Q&A" type