async/await reveals to the consumer that at some point it will exit the code realm for some I/O task and that the result will be asynchronous, you like it or no

async/await reveals to the consumer that at some point it will exit the code realm for some I/O task and that the result will be asynchronous, you like it or not, this is what really happens. Threads approach conceals that fact and wait for the return without you noticing. So, one disadvantage I see, is that you'll need to guess where the time consuming tasks will be done and create threads for them. The most perfomant code will be the one written by who knows better the underlying code.