This read-only bitmap indicates which of the queue's counters, such as bytes, frames, discards, and their 64-bit high-capacity equivalents, are actually supported and valid on this queue. An admin checks this before relying on a specific counter, since not every queue on every platform supports all counter types. For example, if the validHCBytes bit is not set for a given queue, the admin should not trust the rsQueueHCBytes counter for that queue and should use the 32-bit byte counter instead.