Increased unit test coverage for pkg/protocol/header_test

[XiaoYi-byte]

What type of PR is this?

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• [x] This PR title match the format: \<type>(optional scope): \<description>
• [x] The description of this PR title is user-oriented and clear enough for others to understand.
• [x] Attach the PR updating the user documentation if the current PR requires user awareness at the usage level. User docs repo

(Optional) Translate the PR title into Chinese.

提高pkg/protocol/header_test的测试覆盖率从77.2%到80.9%

(Optional) More detailed description for this PR(en: English/zh: Chinese).

en: Increased unit test coverage for pkg/protocol/header_test from 77.2% to 80.9% zh(optional): 提高pkg/protocol/header_test的测试覆盖率从77.2%到80.9%

(Optional) Which issue(s) this PR fixes:

Fixes #257 #### (Optional) The PR that updates user documentation:

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 82.84%. Comparing base (f91ce33) to head (df48c98).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## develop #1074 +/- ## =========================================== + Coverage 82.52% 82.84% +0.31% =========================================== Files 98 98 Lines 10030 10030 =========================================== + Hits 8277 8309 +32 + Misses 1257 1232 -25 + Partials 496 489 -7 ```

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