selectionkey
SelectionKey is a concept often encountered in Java's New I/O (NIO) framework, specifically within the `java.nio.channels` package. It represents the registration of a specific channel with a selector, along with the set of operations that the channel is interested in. When a selector detects that one or more of its registered channels are ready for an operation, it returns a set of SelectionKey objects.
Each SelectionKey object provides access to the channel it is associated with and the selector that registered
Programmers use SelectionKey to determine which channels require attention. By examining the `readyOps()` method of a