httpie allows to get url params and form data from file, by using @ syntax

There are sometimes complicated headers, for example tokens.

It seems this is not yet possible for headers.

Can this feature be added for headers as well?

Probably with a syntax like:

':@'

like:

Referer:http://httpie.org  Cookie:foo=bar  User-Agent:bacon/1.0 FunnyHeader:@somefile

That would be very helpful.