Issue 1853 empty content-encoding

[flsh86]

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[kciesielski]

Question Shouldn't this be a general filtering of all empty headers, with content-encoding being just an example? Looks like empty values are generally valid from the point of view of RFC, but pointless anyway. https://stackoverflow.com/a/12131993

[adamw]

@wydra98 ^ see the comment about empty header values

@kciesielski I think on the low-level, we should retain whatever is returned from the server; and the response.headers is a low-level representation (a multi map string -> string, basically). I agree that when we do any parsing (like when decoding the body), we should filter out empty values