chHeader :: CI BS.ByteString -> BS.ByteString -> [Header] -> Bool
matchHeader name valRegex headers =
  maybe False (=~ valRegex) $ lookup name headers

a
matchHeader :: CI BS.ByteString -> BS.ByteString -> [Header] -> Bool
matchHeader name valRegex headers =
  maybe False (=~ valRegex) $ lookup name headers
matchHeader name valRegex headers =
  maybe False (=~ valRegex) $ lookup name headers