Prefect Polling

Hello

How can I make a function on Prefect that polls for a file to be uploading to a GCS bucket. There is something similar for S3 here - Is there an equivalent to sensors in Prefect? How do I trigger event-driven workflows?.

But in Prefect 2.0 prefect.engine.signals does’nt exist - so what would be the equivalent?

Thanks,
Aniruddha