Manager for creating and obtaining channels. A {@link Channel} is acommunication group consisting of multiple client sessions and the server.
A Channel is created with a {@link Delivery} guarantee. Messagessent on a channel are delivered in a manner that satisfies the channel's delivery guarantee. When possible, channel messages are delivered using the most efficient means to satisfy the delivery guarantee. However, a stronger delivery guarantee may be used to deliver the message if the underlying protocol only supports stronger delivery guarantees. A client session can not be joined to a channel if that client session does not support a protocol satisfying the minimum requirements of the channel's delivery guarantee.
The delivery guarantee of a channel cannot be changed. If different delivery guarantees are needed, then different channels should be used for communication.
@see AppContext#getChannelManager