# control.actor.HELD_WHILE_AWAITING

- **Module:** control.actor
- **Package:** libtmux
- **Language:** Rust
- **Kind:** constant
- **Source:** https://github.com/libtmux/libtmux-rs/blob/8a648c0894dfffc9303583f753b6c8ae01f2fe76/crates/libtmux/src/control/actor.rs#L30
- **Page:** https://libtmux.org/reference/rs/control-actor-held_while_awaiting/

How many events may be held while a reply is outstanding.

Reading continues while something is waiting for a reply, because the reply
arrives on the connection that would otherwise pause. That is bounded by
how long a reply takes, and tmux answers most commands at once -- but not
all. `run-shell` without `-b` answers its own block immediately and then
parks the queue for as long as its shell command runs, so the next command
sent is outstanding for that long and this end would hold events for the
duration. A ceiling turns that into a pause rather than a memory leak.