title: Difference between "x-gzip" and "gzip" for content-encoding
body: <p>In request header, we have <code>accept-encoding: gzip</code>, but got response with encoding <code>x-gzip</code>.</p>
  
  <p>I found <a href="http://www.w3.org/Protocols/rfc2616/rfc2616-sec3.html#sec3.5" rel="noreferrer">this note about x-gzip and gzip</a>:</p>
  
  <blockquote>
    <p>Use of program names for the identification of encoding formats
    is not desirable and is discouraged for future encodings. Their
    use here is representative of historical practice, not good
    design. For compatibility with previous implementations of HTTP,
    applications SHOULD consider "x-gzip" and "x-compress" to be
    equivalent to "gzip" and "compress" respectively.</p>
  </blockquote>
  
  <p>Does it mean <code>x-gzip</code> is equal to <code>gzip</code>? We can simply use the same way to unzip <code>x-gzip</code> content as <code>gzip</code> content?</p>