Allow extend for validating token format or something else

[enif-lee]

aspnetcore-token-authentication/Wd3w.TokenAuthentication/TokenAuthenticationHandler.cs

Lines 54 to 73 in 03c5b0f

	var scheme = Options.Scheme;
	if (authPair.Count != 2)
	return Fail("invalid_format", $"Authorization must be formatted as '{scheme} <token>'");
	if (authPair[0] != Scheme.Name)
	return Fail("invalid_scheme", $"Scheme must be {scheme}");
	if (authPair[1].Length != Options.TokenLength)
	return Fail("invalid_token_length", $"Access Token`s length must be {Options.TokenLength}");
	var accessToken = authPair[1];
	try
	{
	if (!await _authService.IsValidateAsync(accessToken))
	return Fail("invalid_token", $"{scheme} Token({accessToken}) is invalid");
	}
	catch (AuthenticationFailException e)
	{
	return AuthenticateResult.Fail(e);
	}

• How to validating string complexity for access token?