[data] Only dump state once on progress bar close

[omatthew98]

Why are these changes needed?

Close #44979. This also addresses an issue where the bars were misordered in jupyter notebooks (the overall dataset bar showed up last). Examples after the change are below:

Basic Example

import ray
import time

def f(batch):
    time.sleep(0.3)
    return batch

ds = ray.data.range(25, override_num_blocks=25).map_batches(f).map_batches(f, num_cpus=0.2)

for _ in ds.iter_rows():
    time.sleep(0.3)

Jupyter Notebook

basic_ipynb.mov

Terminal

basic_term.mov

Many Operators Example

import ray
import time

def f(batch):
    time.sleep(0.3)
    return batch

ds = ray.data.range(25, override_num_blocks=25).map_batches(f).map_batches(f, num_cpus=0.2).map_batches(f).map_batches(f, num_cpus=0.2).map_batches(f).map_batches(f, num_cpus=0.2).map_batches(f).map_batches(f, num_cpus=0.2).map_batches(f).map_batches(f, num_cpus=0.2)

for _ in ds.iter_rows():
    time.sleep(0.3)

Jupyter Notebook

many_bars_ipynb.mov

Terminal

many_bars_term.mov

Many Datasets Example

import ray
import time

def f(batch):
    time.sleep(0.3)
    return batch

ds1 = ray.data.range(25, override_num_blocks=25).map_batches(f).map_batches(f, num_cpus=0.2).materialize()
ds2 = ray.data.range(25, override_num_blocks=25).map_batches(f).map_batches(f, num_cpus=0.2).materialize()
ds3 = ray.data.range(25, override_num_blocks=25).map_batches(f).map_batches(f, num_cpus=0.2).materialize()

Jupyter Notebook

many_datasets_ipynb.mov

Terminal

many_datasets_term.mov

Related issue number

Close #44979

Checks

• I've signed off every commit(by using the -s flag, i.e., git commit -s) in this PR.
• I've run scripts/format.sh to lint the changes in this PR.
• I've included any doc changes needed for https://docs.ray.io/en/master/.
  • I've added any new APIs to the API Reference. For example, if I added a
    method in Tune, I've added it in doc/source/tune/api/ under the
    corresponding .rst file.
• I've made sure the tests are passing. Note that there might be a few flaky tests, see the recent failures at https://flakey-tests.ray.io/
• Testing Strategy
  • Unit tests
  • Release tests
  • This PR is not tested :(

[scottjlee]

could you add a comment indicating why this must happen prior to operator bars being initialized, so readers know about this fix?

[scottjlee]

same here, let's explain why we are hiding/unhiding the bar

[scottjlee]

nit: we can put this in the original order to minimize change