I was also wondering why .call accepts lambda functions as argument, but .event does not.
I have to say that even after working a few months with Mbed OS, I haven’t completely understood the difference between these two functions. They seem to do the same thing, but I’ve noticed that .event and .call don’t behave the same. For example, using .event() would trigger an EventQueue overflow after a few minutes while .call was working fine with the exact same arguments. Is there a difference between .event and .call in how Mbed handles the Threads that run the EventQueue somehow?