worker_spi.naptime in worker_spi example

Hello!

I am trying to create a background worker where I can pass in via SQL
interface the naptime. I'm not sure how to do this. In the worker_spi
example, _PG_init creates a configuration using the static variable
worker_spi_naptime, but then it appears to call in worker_spi_main in the
WaitLatch function the same variable worker_spi_naptime without referencing
the configuration created in _PG_init. Am I missing something here?

I could see how to pass in an int for naptime via the SQL interface but I'm
not sure what the function is of this configuration.

Thanks!
Jeremy