http2 seems to be slow

Hi

I have tested speed of http2 library and it is much slower comparing to http. I tested with client and server being on my local. Server is written in Go and client in Dart. To downloaded 100mb file with HttpClient it takes 4s and http2 takes 15s.
I faced this issue with GRPC. We are downloading files with GRPC streams and speed depending on how far the server is, can be 8 times slower comparing to http download. I was trying to isolate the issue and it seems http2 package seems to be the main problem.
I have Dart VM version: 2.8.4
and tested with
http2: ^1.0.0
http: ^0.12.2

I used the code from "minimal example" to download file with http2. Is there a way to improve speed?

Start by running the HTTP/2 package's minimal example with the reported Dart and package versions, then reproduce the 100 MB client/server comparison against HttpClient. Compare the HTTP/2 and gRPC stream behavior and document a confirmed bottleneck or actionable performance issue; done means the slowdown is explained by evidence or a focused fix can be specified.

Written by the indexing model from the issue text.