/**
 * Contains constant definitions for the HTTP header field names. See:
 *
 * <ul>
 *   <li><a href="http://www.ietf.org/rfc/rfc2109.txt">RFC 2109</a>
 *   <li><a href="http://www.ietf.org/rfc/rfc2183.txt">RFC 2183</a>
 *   <li><a href="http://www.ietf.org/rfc/rfc2616.txt">RFC 2616</a>
 *   <li><a href="http://www.ietf.org/rfc/rfc2965.txt">RFC 2965</a>
 *   <li><a href="http://www.ietf.org/rfc/rfc5988.txt">RFC 5988</a>
 * </ul>
 *

     * expected</i>, but not absolutely required, to have the following properties:
     *
     * <ul>
     *   <li>Its execution does not cause any observable side effects.
     *   <li>The computation is <i>consistent with equals</i>; that is, {@link Objects#equal
     *       Objects.equal}{@code (k1, k2) &&} {@link Objects#equal}{@code (v1, v2)} implies that