Support PPE profiling for S3

[KantaTamura]

This PR resolves the S3 task in #258

Sample program to check tracing

import json
import pytorch_pfn_extras as ppe

from pfio.v2 import S3, Path, from_url

def p():
    tracer = ppe.profiler.get_tracer()
    tracer.clear()

    fil = 0

    with from_url('pfs1://cluster-tutorial/', trace=True) as fs:
        assert isinstance(fs, S3)

        for f in fs.list(recursive=True):
            if f == "imagenet-classification.zip":
                continue

            with fs.open(f, 'rb') as fp:
                tmp = fp.read()

            fil += 1

            if fil > 10:
                break

    print(fil, "files")

    dict = tracer.state_dict()
    keys = [event["name"] for event in json.loads(dict["_event_list"])]
    print(keys)

    w = ppe.writing.SimpleWriter(out_dir="")
    tracer.initialize_writer("trace_s3.json", w)
    tracer.flush("trace_s3.json", w)

p()

output

11 files
['pfio.v2.S3:list-0', 'pfio.v2.S3:open', 'pfio.v2.S3:read', 'pfio.v2.S3:exit-context', 'pfio.v2.S3:list-1', 'pfio.v2.S3:open', 'pfio.v2.S3:read', 'pfio.v2.S3:exit-context', 'pfio.v2.S3:list-2', 'pfio.v2.S3:open', 'pfio.v2.S3:read', 'pfio.v2.S3:exit-context', 'pfio.v2.S3:list-3', 'pfio.v2.S3:open', 'pfio.v2.S3:read', 'pfio.v2.S3:exit-context', 'pfio.v2.S3:list-4', 'pfio.v2.S3:open', 'pfio.v2.S3:read', 'pfio.v2.S3:exit-context', 'pfio.v2.S3:list-5', 'pfio.v2.S3:open', 'pfio.v2.S3:read', 'pfio.v2.S3:exit-context', 'pfio.v2.S3:list-6', 'pfio.v2.S3:open', 'pfio.v2.S3:read', 'pfio.v2.S3:exit-context', 'pfio.v2.S3:list-7', 'pfio.v2.S3:open', 'pfio.v2.S3:read', 'pfio.v2.S3:exit-context', 'pfio.v2.S3:list-8', 'pfio.v2.S3:open', 'pfio.v2.S3:read', 'pfio.v2.S3:exit-context', 'pfio.v2.S3:list-9', 'pfio.v2.S3:open', 'pfio.v2.S3:read', 'pfio.v2.S3:exit-context', 'pfio.v2.S3:list-10', 'pfio.v2.S3:open', 'pfio.v2.S3:read', 'pfio.v2.S3:exit-context', 'pfio.v2.S3:list-11']

rendering of the output json file (trace.json) with chrome://tracing is shown below

[KantaTamura]

add profiling boto3 api

[k5342]

Overall, it looks good. I have one minor suggestion.

[k5342]

It's better to switch here between the vanilla boto3 and the wrapped boto3 client by self.trace as well as Local fs does.

pfio/pfio/v2/local.py

Lines 123 to 127 in 9bf5900

	# Add ppe recorder to io class methods (e.g. read, write)
	if self.trace:
	return LocalProfileIOWrapper(fp)
	else:
	return fp

[KantaTamura]

Forgot to change from test code ...

[KantaTamura]

fix and rebase master branch

[k5342]

PR #343 merge raised a conflict. Could you resolve the conflict before merging this, please?