How can I know whether postgres is currently running synchronous or asynchronous replication? I see from ps that:

postgres: wal sender process replicator X.X.X.X(38681) streaming 0/17AF5438


But is there any way for me to know whether it is synchronous or asynchronous? I made the relevant changes in postgresql.conf to switch from synchronous to asynchronous and restarted the postgres service, but I wanted to double check that the changes were parsed correctly and I am in fact running asynchronously.
If:

SHOW synchronous_standby_names;


on the master that's expected to have synchronous replicas reports a non-empty value, then synchronous replication is active.