E1601. guard() called after close()
Severity: ERROR. Programmer error.
What happened
Your code called Client.guard() on a Client that already had
close() called on it. The SDK refuses to continue auditing because
the audit sinks have been drained and shut down.
How to fix
Restructure your code so close() runs exactly once, at the end of
the agent's lifecycle. The most common cause is putting close()
inside a finally that fires per-iteration instead of once.