Function wait_async

pub fn wait_async(
    typed_array: &Int32Array,
    index: u32,
    value: i32,
) -> Result<Object, JsValue>

The static Atomics.waitAsync() method verifies that a given position in an Int32Array still contains a given value and if so sleeps, awaiting a wakeup or a timeout. It returns an object with two properties. The first property async is a boolean which if true indicates that the second property value is a promise. If async is false then value is a string whether equal to either “not-equal” or “timed-out”. Note: This operation only works with a shared Int32Array and may be used on the main thread.

You should use wait_async_bigint to operate on a BigInt64Array.

MDN documentation