Support for Content-Encoding:gzip(?)

[cmdcolin]

Content-Encoding:gzip often confuses not just jbrowse but the web browser also

In some limited cases, we can skip running pako unzip steps like this PR demonstrates and this will decode the BAM header, but it still fails on the actual BAM data. the error at that point I believe comes from the browser, and not any JS code, so I think this may be the limiting factor

example of allowing the header to be read
https://github.com/GMOD/bam-js/compare/t1?expand=1

[cmdcolin]

the behavior for this can vary slightly between browsers, so it's a bit tricky. in general, the rule to best play by is to not set Content-Encoding: gzip

[cmdcolin]

xref GMOD/jbrowse-components#4120 another content-encoding:gzip related issue most likely