Sending SIZE <file> during site-to-site transfers for progress

[neoxed]

During site-to-site transfers, FlashFXP currently bases the file's progress on the previous transfer's speed (size/time). Rather than estimating the approximate remaining time, what about periodically sending a SIZE <file> during the transfer? By doing so, you would be able to calculate the remaining time and completed amount a lot more accurately.

Provided this does not break an RFC, I would think it's a worthy implementation.