Creates the appropriate instance of OutputMetricsUpdater.
is true, the created instance will be updating task metrics so
that Spark will report them in the UI. Remember that this is supported for Spark 1.2+.
If CassandraConnectorSource is registered
in Spark metrics system, the created instance will be
updating the included Codahale metrics. In order to register CassandraConnectorSource you need
to add it to the metrics configuration file.
task context of a task for which this metrics updater is created