Fix bug: The master node may repeatedly dump the same batch of binlogs

[takenliu]

The master node may repeatedly dump the same batch of binlogs, when the slave node is busy, leading to repeated timeouts and reconnections in master-slave synchronization.

#447

Description

Motivation and Context

How Has This Been Tested?

Types of Changes

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist:

• Code follows the code style of this project.
• Change requires a change to the documentation.
• I have updated the documentation accordingly.