Easy way to pass additional data from an Authenticator to a Spawner

[Sergey Zhemzhitsky]

Hi there! 

I'm implementing custom jwt-authenticator and it needs to pass jwt claims to a spawner. 

Is it safe enough just to assign these claims to authenticator's class field and then pass them to the spawner in the pre_spawn_start callback?

I don't need encrypted auth_state in my case, so I'm trying to figure out whether there is a simpler way to pass additional user-specific data from authenticator to the spawner.