Use the QDecompressHelper to feed the grpc HTTP/2 streams with compressed data. The QDecompressHelper already supports the wellknown compression methods, so we only need to feed it properly according to grpc-accept-encoding/grpc-encoding headers and control the data flow.

gRFC: https://github.com/grpc/grpc/blob/master/doc/compression.md
core compresison: https://github.com/grpc/grpc/blob/master/doc/compression_cookbook.md

overview: https://grpc.io/docs/guides/compression/