simplify simple log format

Signed-off-by: Eddie Teng <[email protected]>

fix unit tests

Signed-off-by: Eddie Teng <[email protected]>

fix unit tests

Signed-off-by: Eddie Teng <[email protected]>

timestamp use time type

Merge pull request #15 from EdgarTeng/feature/fields-support

Feature/fields support

add readme

Merge pull request #2 from EdgarTeng/bugfix/json-fields

support json fields