Request headers with first character lowercase does not work

[ThieuNguyen]

it return 404 Not found if the request headers is:

  headers:
    myheader:
      - "abc"

but it's okay if I change the request header to:

  headers:
    Myheader:
      - "abc"

P/s: work with My_header, doesn't work with My_Header

[jdietrich-tc]

I ran into this as well. I did some digging and it is in the core go library. All headers go though
https://pkg.go.dev/net/textproto#CanonicalMIMEHeaderKey