mirror:Add the printing of event time

[dormanze]

Community Contribution License

All community contributions in this pull request are licensed to the project maintainers
under the terms of the Apache 2 license.
By creating this pull request I represent that I have the right to license the
contributions to the project maintainers under the Apache 2 license.

Description

The event time is printed in watch mode.

Motivation and Context

How to test this PR?

setp1:
keep watch

mc mirror -w test/bucket1 test/bucket2 --quiet

setp2:
upload or remove file.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Optimization (provides speedup with no functional changes)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• Fixes a regression (If yes, please add commit-id or PR # here)
• Unit tests added/updated
• Internal documentation updated
• Create a documentation update request here

[klauspost]

@dormanze Could you address the issues mentioned?

[dormanze]

@dormanze Could you address the issues mentioned?

Okay, I've solved it. Please review. Thank you very much.

[klauspost]

LGTM