Motivation:
The HTTP/2 spec does not restrict headers to being String. The current
implementation of the HTTP/2 codec uses Strings as header keys and
values. We should change this so that header keys and values allow
binary values.
Modifications:
Making Http2Headers based on AsciiString, which is a wrapper around a
byte[].
Various changes throughout the HTTP/2 codec to use the new interface.
Result:
HTTP/2 codec no longer requires string headers.