Passive network monitoring is a vital activity for network operators that want to guarantee a good level of quality of service to the users of the network, as it allows them to observer real user data and detect performance and health issues. One of the variables that mostly impacts the effectiveness of passive network monitoring is the wire image of the protocol under analysis, which in the case of QUIC is very limited. Furthermore, the Spin Bit defined in the QUIC specification is optional and it is rarely implemented in existing QUIC libraries, making it unusable since it must be supported and agreed upon by both endpoints.