Merge pull request !800 from YuhanShi/ExplainJob_v1.0

Merge pull request !795 from TonyNG/master

json return null if ExplainManager returns None

use fromtimestamp

use fromtimestamp

wrong name

wrong json key

use offset as page offset

enhance comments

rm mock_explainer_api.py

update copyright year 2020

remove unused import

modification for parser

modification for parser with containers

fix bugs for parser

fix value vacancy for parser

fix typos for parser

adaptation for proto modification

rearrange image data from events

fix small typo

add comments and some error message

delete example

modify init setting of parser

modify some structure of parser

fix pylint warnings

modify parser for parsing one event every time

modify for review

add some comments

modify proto file

modify for open source comments