private unsafe static BsonDocument SerializeKey(Jwk key)
{
using var bufferWriter = new PooledByteBufferWriter(1024);
using var jsonWriter = new Utf8JsonWriter(bufferWriter);
jsonWriter.WriteStartObject();
key.WriteTo(jsonWriter);
jsonWriter.WriteEndObject();
jsonWriter.Flush();
return(BsonDocument.Parse(Encoding.UTF8.GetString(bufferWriter.WrittenSpan)));
}