EventLoop

1)EventExecutorGroup: The EventExecutorGroup is responsible for providing the EventExecutor's to use via its next() method.

2)AbstractEventExecutorGroup: Abstract base class for EventExecutorGroup implementations.

3)MultithreadEventExecutorGroup: Abstract base class for EventExecutorGroup implementations that handles their tasks with multiple threads at the same time.

4)MultithreadEventLoopGroup: Abstract base class for EventLoopGroup implementations that handles their tasks with multiple threads at the same time.

5)NioEventLoopGroup: MultithreadEventLoopGroup implementations which is used for NIO Selector based Channels.