Missing hash key: HTTP::Headers::Key(@name="Host") when before_request_callbacks

[msa7]

I have issue in PR msa7/multi_auth#12

       Missing hash key: HTTP::Headers::Key(@name="Host") (KeyError)
         from /usr/share/crystal/src/hash.cr:0:9 in '[]'
         from /usr/share/crystal/src/http/headers.cr:66:5 in '[]'
         from /usr/share/crystal/src/oauth/signature.cr:92:5 in 'host_and_port'
         from /usr/share/crystal/src/oauth/signature.cr:43:18 in 'base_string'
         from /usr/share/crystal/src/oauth/signature.cr:7:5 in 'base_string'
         from /usr/share/crystal/src/oauth/signature.cr:21:5 in 'compute'
         from /usr/share/crystal/src/oauth/signature.cr:26:5 in 'authorization_header'
         from /usr/share/crystal/src/oauth/oauth.cr:56:5 in 'oauth_header'
         from /usr/share/crystal/src/oauth/oauth.cr:48:40 in 'authenticate'
         from /usr/share/crystal/src/oauth/oauth.cr:43:7 in '->'
         from /usr/share/crystal/src/http/client.cr:255:3 in 'run_before_request_callbacks'