Unable to use await for Timer.timeout signal

[tishin]

A simplified node example:

@Godot
class TimerNode: Node {
    
    let timer = Timer()
    
    override func _ready() {
        addChild(node: timer)
        
        timer.start()
        GD.print("started")
        
        Task {
            await timer.timeout.emitted
            GD.print("emitted")
        }
    }
    
}

Awaiting for timeout throws an error:

ERROR: Caller thread can't call this function in this node (/root/Timer/@Timer@2). Use call_deferred() or call_thread_group() instead.
at: connect (scene/main/node.cpp:3706)
Warning, error connecting to signal timeout: errInvalidParameter

And the second print does not happen.