Add download_job_result method to JobAPI

[chezou]

This method downloads the result of a job to a
local file in msgpack.gz format. It can specify
thread number for parallel download.

File validation

Confirmed that checksum is the same as a downloaded file by TD toolbelt.

$ shasum 2172017217*
5e227ef6582fd216ce1f0d8b81d43a4a6274aff6  2172017217.msgpack.gz
5e227ef6582fd216ce1f0d8b81d43a4a6274aff6  2172017217_toolbelt.msgpack.gz

Download speed comparison

• TD Toolbelt: 37 mins (including one retry)
• td-client-python with 6 threads: 4 mins

$ time /Users/ariga/.gem/ruby/2.6.0/bin/td job:show 2172017217 -f msgpack.gz -o 2172017217_toolbelt.msgpack.gz
JobID       : 2172017217
Status      : success
Type        : presto
Database    : aki_audience_large
Start At    : 2024-08-17 08:52:04 UTC
End At      : 2024-08-17 09:03:29 UTC
Priority    : NORMAL
Retry limit : 0
Output      :
Query       : select * from behavior_1 limit 100_000_000
Result size : 2.84 GB
Result      :
EOFError: httpclient IncompleteError. Retrying after 5 seconds...ack.gz in msgpack.gz format 966.9 MB /  2.8 GB : ======= 33 ========
NOTE: the job result is being written to 2172017217_toolbelt.msgpack.gz in msgpack.gz format  2.8 GB /  2.8 GB : =========================== 100 ===========================
written to 2172017217_toolbelt.msgpack.gz in msgpack.gz format
Use '-v' option to show detailed messages.
/Users/ariga/.gem/ruby/2.6.0/bin/td job:show 2172017217 -f msgpack.gz -o   71.05s user 62.49s system 5% cpu 37:38.02 total

>>> import tdclient; import os; td = tdclient.Client(apikey=os.environ["TD_API_KEY"])
>>> import time; s = time.time(); td.download_job_result("2172017217", "2172017217.msgpack.gz"); print(f"elapsed time: {time.time() - s} sec")
True
elapsed time: 240.56217789649963 sec

[tung-vu-td]

LGTM