Explain non-blocking I/O
Explain non-blocking I/O

Motivation:

It would be nice to have a bit of an explainer on the name.

Modifications:

Add a paragraph explaining non-blocking I/O.

Result:

There is now a paragraph in the readme explaining non-blocking I/O.

apple/swift-nio,apple/swift-nio,apple/swift-nio,apple/swift-nio,apple/swift-nio