Fix tcollect of ProgressLoggingFoldable

[andreas-theo]

Hello,

I have been carrying this patch to Transducers in my dev-ed version of Transducers for months now, but never found the time to submit a PR. This PR fixes #10 and allows one to define transducers wrapped with withprogress to use progress loggers. This is very nice, as it allows one to use the built-in support for ProgressLogging.jl in Pluto and VS Code together with Transducers and Folds.

For example

using Logging: global_logger
using TerminalLoggers: TerminalLogger
using Transducers

global_logger(TerminalLogger())

julia> tcollect(data |> withprogress |> Map() do (y, x); y+x end)
Progress: 100%|██████████████████████████████████████████████████████████████████████████| Time: 0:00:00
9-element Vector{Int64}:
 3
 4
 5
 4
 5
 6
 5
 6
 7

[MasonProtter]

Hi @andreas-theo, thanks for submitting this. I was going to complain that this wasn't really a good solution because it'll only update the progress meter once one of the serial chunks finishes, but then I looked at the old implementation and found that it actually does the same thing. So I guess this isn't actually any worse than how it used to work.

Still not sure I really like this version, but I guess it's good enough for now, and I can later consider the best way to make it update more often in a future patch.

[andreas-theo]

Indeed, I agree. I'd be open to implementing a better solution with some guidance from your side.

[MasonProtter]

Hi Andreas, sorry for the late reply. I'd love to help guide you with this, but life has been pretty hectic recently and I haven't had much time for Transducers.

I'm hoping that in a couple weeks I can write up some thoughts on how it can be handled.