Sample showing multiple readers from the same reader group

[elizabethbain]

This sample is meant to show the behavior of Pravega when there are multiple readers on the same stream where each reader is from the same reader group. This is to be contrasted with the sample showing multiple readers on the same stream from different reader groups. When the readers are from the same group, the data being processed is divided between them by reading different segments. Currently the samples we have only have one writer and one reader to a stream. This sample and the sample with multiple readers from different reader groups is to illustrate the simple interactions and behavior of Pravega when there are multiple readers of the same data.
Scenario

1. A writer is writing to a given stream with specific events.
2. Two readers (Reader A and Reader B) are started for reading from the stream, offset by a short amount of time
3. Each reader writes the data to stdout with its id appended to it to identify which reader put out the event.
4. The output should demonstrate that an event is only seen by Reader A or Reader B, but not both.