Please add the support for "Flattened JWS JSON Serialization Syntax" according https://www.rfc-editor.org/rfc/rfc7515#section-7.2.2 . My use case is to write a ACME client in c# and the ACME RFC requires the use of "Flattened JWS JSON Serialization Syntax" (https://www.rfc-editor.org/rfc/rfc8555.html#section-6.2).