worker_spi.naptime in worker_spi example

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?