Pick the destination for a given message.
Pick the destination for a given message. Normally it picks one of the
passed routees, but in the end it is up to the implementation to
return whatever Routee to use for sending a specific message.
When implemented from Java it can be good to know that
routees.apply(index) can be used to get an element
from the IndexedSeq.
Randomly selects one of the target routees to send a message to