When a panic happens, WiredTiger sets the connection level panic flag and then calls the underlying application error function with the WT_PANIC flag.

As soon as the connection level panic flag is set, application threads will return WT_PANIC from WiredTiger API calls, those threads might race with the thread of control setting the panic flag, and the application might save stack information from an uninteresting API thread, simply because it's the first WT_PANIC the application saw.

Change WiredTiger to wait for the underlying application error function to return before setting the connection-level panic flag, ensuring the application has the opportunity to save the interesting thread stack information.