||The CometEvent interface.
||A Comet filter, similar to regular filters, performs filtering tasks on either
the request to a resource (a Comet servlet), or on the response from a resource, or both.
||A CometFilterChain is an object provided by the servlet container to the developer
giving a view into the invocation chain of a filtered event for a resource.
||This interface should be implemented by servlets which would like to handle
asynchronous IO, receiving events when data is available for reading, and
being able to output data without the need for being invoked by the container.