Two commands have been added to the `jcmd` command line tool to print information that may be useful when diagnosing issues with virtual threads.

`jcmd <pid> Thread.vthread_scheduler` prints the virtual thread scheduler, the target parallelism, number of threads, and other useful counters. The output also includes the delayed task schedulers that support virtual threads doing timed operations.

`jcmd <pid> Thread.vthread_pollers` prints the I/O pollers that support virtual threads doing blocking network I/O operations.