operator_on_subscribe

Run a callback when a subscription is established.

See Also

• TapOperator - Mirror all signals into another observer.
• TapNextOperator - Run a callback for each next value while letting signals pass through.
• OnNextOperator - Invoke a callback for each value that can also decide whether to forward it.
• FinalizeOperator - Execute cleanup when the observable finishes or unsubscribes.

Example

cargo run -p rx_core --example operator_on_subscribe_example

let _subscription = (1..=5)
    .into_observable()
    .on_subscribe(|destination| destination.next(99))
    .subscribe(PrintObserver::new("on_subscribe_operator"));

Output:

on_subscribe_operator - next: 99
on_subscribe_operator - next: 1
on_subscribe_operator - next: 2
on_subscribe_operator - next: 3
on_subscribe_operator - next: 4
on_subscribe_operator - next: 5
on_subscribe_operator - completed
on_subscribe_operator - unsubscribed