fix(http2): bound header size to 256 KiB - #1978

brianquinlan wants to merge 5 commits into

fix(http2): bound header size to 256 KiB#1978
brianquinlan wants to merge 5 commits into
dart-lang:masterfrom
brianquinlan:unbound_continuation

fix(http2): limit header block size to 256 KiB