It seems the lagacy HttpURLConnection will accept LF as well as CRLF as header separator. For the sake of interoperability we might want to consider the same with the new HttpClient.

RFC 7230 says:

```Although the line terminator for the start-line and header fields is
   the sequence CRLF, a recipient MAY recognize a single LF as a line
   terminator and ignore any preceding CR.```

This doesn't seem to extend to the CRLF terminator used to separate body chunks though.