Returns the next packet reference, or null if the end
has been reached.
Returns the minimal start time of the remaining packets to be iterated through.
At least one packet must have been consumed so this method can return a valid
value. If no packet has been consumed (i.e. next() has never been called), this
method will return 0.
Discards this iterator. This is automatically performed when IPacketStoreIterator.next()
returns null, but can be performed manually sooner.