Setting decompression WindowSize? about zstd HOT 1 OPEN

Hi @siara-cc,

It looks like the zstd C API allows you to set the max window size: https://github.com/DataDog/zstd/blob/1.x/zstd.h#L2075-L2082

Currently to keep things simple, the Go library doesn't expose that C object (creates and keep it internally): https://github.com/DataDog/zstd/blob/1.x/zstd_stream.go#L397

but I've seen the need to set different more advanced options from different use cases so I will mark this one as a feature request. If you are willing to contribute to add a new interface (maybe NewReaderWithOptions(ctx *C.ZSTD_DCtx, r io.Reader, dict []byte)), I'd be happy to review the PR!

If this is just for testing, you can probably just call ZSTD_DCtx_setMaxWindowSize here: https://github.com/DataDog/zstd/blob/1.x/zstd_stream.go#L398 by modifying your local DataDog/zstd library

from zstd.