/**
* Challenge Number 1!
*
* getSyncLogSource returns an object with a one method: pop() which will return a LogEntry.
*
* A LogEntry is simply an object of the form:
* {
*      date: Date,
*      msg: String,
* }
*
* All LogEntries from a given log source are guaranteed to be popped in chronological order.
* Eventually a log source will end and return boolean false.
*
* Your job is simple: print the sorted merge of all LogEntries across `n` log sources.
*
* Call `printer.print(logEntry)` to print each entry of the merged output as they are ready.
* This function will ensure that what you print is in fact in chronological order.
* Call 'printer.done()' at the end to get a few stats on your solution!
*/