mars subscribe <filter>
Filter is a key=value;key=value string mapping to the subscribe frame.
mars subscribe 'kind=agent;namespace=l1fe'
# 15:00:24 EntryCreated did:oas:verbage:agent:cs-router@1.0.4
# 15:00:21 AttestationAdded did:oas:l1fe:agent:web-research@3.4.0 type=eval-passed
Press Ctrl+C to stop. On reconnect with --since <cursor>, the stream
resumes from where you left off.