/// <summary>Determines whether the <see cref="JwtHeaderDocument"/> contains the specified header parameter.</summary>
 /// <param name="headerParameterName"></param>
 /// <returns></returns>
 public bool ContainsHeaderParameter(string headerParameterName)
 => _document.ContainsKey(headerParameterName);
 /// <summary>Determines whether the <see cref="JwtPayloadDocument"/> contains the specified claim.</summary>
 /// <param name="claimName"></param>
 /// <returns></returns>
 public bool ContainsClaim(string claimName)
 => _document.ContainsKey(claimName);