Can't build.

[MrSorcus]

laptop% crystal build h2.cr
Error in src/io/hexdump.cr:4: this 'initialize' doesn't explicitly initialize instance variable '@output' of IO::Hexdump, rendering it nilable

The instance variable '@output' is initialized in other 'initialize' methods,
and by not initializing it here it's not clear if the variable is supposed
to be nilable or if this is a mistake.

To fix this error, either assign nil to it here:

  @output = nil

Or declare it as nilable outside at the type level:

  @output : (IO)?

  def initialize(@io : IO, @logger : Logger|Logger::Dummy, @read = true, @write = true)

[MrSorcus]

I'm not sure, but https://github.com/ysbaddaden/http2/blob/master/src/io/hexdump.cr conflict with https://github.com/crystal-lang/crystal/blob/master/src/io/hexdump.cr right?

[ysbaddaden]

Yes, comment-out things related to IO::Hexdump and it should work better.

[MrSorcus]

Thanks.
Do you have any plan for fix it in future? Or it's unmaintained?

[ysbaddaden]

Fixed in master.

It's been a long and hard journey to implement the HTTP/2 protocol, but it's no longer actively developed.