It is no longer required, as we can use `<H as Header>::header_name()`.
BREAKING CHANGE: Implementations of Header will need to adjust the
header_name method. It no longer takes any arguments.
It is no longer required, as we can use `<H as Header>::header_name()`.
BREAKING CHANGE: Implementations of Header will need to adjust the
header_name method. It no longer takes any arguments.