[Cyberduck-trac] [Cyberduck] #7815: Tx rate and time remaining estimate inaccurate on resumed transfers

[Cyberduck]

#7815: Tx rate and time remaining estimate inaccurate on resumed transfers
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    Reporter:  jg3     |      Owner:
        Type:  defect  |     Status:  new
    Priority:  normal  |  Milestone:
   Component:  core    |    Version:  4.4.3
    Severity:  normal  |   Keywords:
Architecture:          |   Platform:
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 When resuming downloads, the transfer rate (and accordingly, the remaining
 time estimate) is calculated incorrectly. For example:

 Assume 10MB file.

 5MB was previously downloaded.

 DL is resumed.

 At first, the tx rate is astronomically high and the estimated remaining
 time shows just a few seconds. It looks like the rate/time calculation is
 thinking that the first 5MB were downloaded instantaneously.

 Suppose it takes 1 minute to DL the next 1MB. Now perhaps the rate would
 show 102.4KB/s (i.e. 6MB in 1 minute) and estimate less than 1 minute left
 (to DL the remaining 4MB) when in fact the rate has been 17KB/s (1MB in 1
 minute) and it should be 4 minutes remaining.

 In other words, I think the calculation is taking into account the
 previously-downloaded portion, which throws things off. It would be much
 more helpful if only the size remaining of the file since "resume" were
 taken into account - then we could have more accurate time (and transfer
 rate) estimates.

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Ticket URL: <https://trac.cyberduck.io/ticket/7815>
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