It is absolutely safe. Coroutine machinery guarant...

# coroutines

[elizarov]

It is absolutely safe. Coroutine machinery guarantees that execution is sequential (i.e. non-concurrent), despite being spread over different threads. The definition of sequential execution includes visibility of writes/puts. In more technical terms, the execution before suspension point always happens-before execution after suspension point. If you are interested in implementation details, it is actually not the machinery itself, but the contract of CompletableFuture.whenComplete method (which is used to implement await) that provides the corresponding happens-before edge.