Signal (NOT Cancel) A BackgroundWorker?

Is it possible to send information to a BackgroundWorker thread while it is running? Here is my scenario: Parent thread calls background thread to send a data request to a database. If it's a big complicated query it can take a while for the db to respond, so putting the db request on the background worker thread is great. My app can do other stuff while the one thread waits for the db.

Now, db responds with beginning of data. I want my background thread to report back meta data about the result set to the parent thread. No problem there, I can use a custom user state object and the ReportProgress method. But now, how to I send a signal from the parent thread back to the worker thread? I want the background thread to wait while the parent thread does something, and then tells the worker thread to keep going or quit. I know how to cancel a background thread, but I want the parent to be able tell the child some information other than "cancel". Here's one way to think about it:

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