Constant INTERACTIVE_MAX_QUEUE_WAIT 

pub const INTERACTIVE_MAX_QUEUE_WAIT: Duration;

The longest an interactive call waits for a permit before giving up. With the 30 s interactive time limit (purpose), a call ends within 40 s, inside the pane’s 45 s RPC timeout (ambient-rpc.ts), so a reply is never paid for after the pane has stopped waiting for it.