Awaitable isMaster commands can add noise to currentOp. While it's currently possible to filter them out using filters like {command.isMaster:{$exists:false}}, {command.maxAwaitTimeMS: {$exists:false}}, {command.maxAwaitTimeMS: "$ne":10000}} and/or {"ns":{"$ne":"admin.$cmd"}, it would be nice to have an explicit field to filter on, such as "awaitable":true.

Or even, if possible, awaiting: true to indicate the operation is both awaitable AND that the clock is ticking on its awaitTimeMS. This may also be of use for Change Stream and oplog tailing operations which are (I believe) the only other places currently using this sort of mechanism.

Ideally, given the prevalence of these awaitable isMaster commands in 4.4+, an explicit filter would not be required to hide them.