How does a serial dispatch queue guarantee resource protection?
//my_serial_queue is a serial_dispatch_queue dispatch_async(my_serial_queue, ^{ //access a shared resource such as a bank account balance [self changeBankAccountBalance]; }); If I submit 100 tasks that each access and mutate a bank account balance, I understand that a serial queue will execute each task sequentially, but do these tasks finish sequentially as well when using dispatch_async? What if task #23 that I submit asynchronously to the serial queue takes a really long time to finish? Would task #24 start only when task #23 is done, or would task #24 begin before task #23 is done? If so,