Editor: RLE (Run Length Encoding) is a very simple compression Algorithm, mainly used for streams of data with strings of repeating characters. Please note that you might find different, not compatible implementations.
LastCompressionRatio as Double: Well, exactly that, the compression achieved in the last operation. The algorithm calculates it both on compression and decompression. It's given in the form Output Size / Input Size, so the smaller it is the better.
LastCount as Double: time that the last operation took, given in seconds.