Whether the state already exists
Get the state if it exists, otherwise it will throw
java.util.NoSuchElementException If the state does not exist.
Whether the state is timing out and going to be removed by the system after the current batch.
Remove the state if it exists.
Update the state with a new value.
java.lang.IllegalArgumentException If the state has already been removed, or is
going to be removed
Get the state as a scala.Option.