public override string ToString()
{
var buffer = new StringBuilder (64);
buffer.AppendFormat (
"{0} {1} HTTP/{2}{3}", _method, _rawUrl, ProtocolVersion, CrLf);
var headers = Headers;
foreach (var key in headers.AllKeys)
buffer.AppendFormat ("{0}: {1}{2}", key, headers [key], CrLf);
buffer.Append (CrLf);
var entity = EntityBody;
if (entity.Length > 0)
buffer.Append (entity);
return buffer.ToString ();
}