public static IResponse ByteArray(this IHas @this, Func <byte[], bool> predicate)
 => @this.AssertContentMatches(content => content.ReadAsByteArrayAsync().GetAwaiter().GetResult(), predicate);
 public static IResponse String(this IHas @this, Func <string, bool> predicate)
 => @this.AssertContentMatches(content => content.ReadAsStringAsync().GetAwaiter().GetResult(), predicate);
 public static IResponse Content(this IHas @this, Func <HttpContent, bool> predicate)
 => @this.AssertContentMatches(content => content, predicate);