refactor: use strings.Builder to improve performance (#7364)

* refactor: use strings.Builder to improve performance

Signed-off-by: zjumathcode <pai314159@2980.com>

* refactor: small builder improvements per review (WriteByte / split writes)

also revert builder change in client_test.go

refactor(logging): build IP mask output via join of parts (more efficient)

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Signed-off-by: zjumathcode <pai314159@2980.com>
Co-authored-by: Francis Lavoie <lavofr@gmail.com>