Async

Asynchrony, in software programming, refers to events that occur outside of the primary program flow and methods for dealing with them. External events such as signals or activities prompted by a program that occur at the same time as program execution without causing the program to block and wait for results are examples of this category. Asynchronous input/output is an example of the latter case, and allows programs to issue commands to storage or network devices that can process these requests while the processor continues executing.