I did some search on the web but couldn't find any documentation for
0.8 so I am trying to ask here:
KeyedMessage is introduced in 0.8.0:
class KeyedMessage[K, V](val topic: String, val key: K, val message: V)
Does the parameter "key" = "partition key"?
If I build a KeyedMessage with a specific key string, then the message
will be stored to this partition, right?
If I build a KeyedMessage without a key, then the message will be
distributed to a random partition belonging to this topic? Or will it
always use a certain default partition?