Rebus can be configured to enable "saga auditing", which plugs in a mechanism that will generate a snapshot of each saga state, outputting it to some kind of "snapshot storage".

You can enable it by going

services.AddRebus(
	configure => configure
		.Transport(t => (...))
		.Options(o => o.EnableSagaAuditing().<1>)
);

where <1> can then configure some kind of snapshot storage. A simple approach would be to simply output saga state snapshots to Rebus' normal logger, which can be enabled by going

services.AddRebus(
    configure => configure
        .Transport(t => t.(...))
        .Options(o => o.EnableSagaAuditing().OutputToLog())
);

Other types of snapshot storage can be had, too – e.g. by installing the Rebus.SqlServer package and using the .StoreInSqlServer(...) extension.