Bug: Request keep alive doesn't work

[xiaodong2008]

What is the current behavior?

Request keep alive doesn't work

What is the expected behavior?

Request keep alive feat

Steps to reproduce the problem

Create a request instance with config.keepalive

Link to minimal reproduction

No response

System Info

No response

Any additional comments?

No response

Confirmations

• [X] I'm using/tried the latest version of fastjs and the bug is still there
• [X] I have read the Code of Conduct
• [X] I have read the Issue Reporting Guidelines
• [X] I have searched for similar issues in both open and closed tickets and cannot find a duplicate
• [X] I know that any inappropriate content may cause the maintainer to take action base on the Code of Conduct

[xiaodong2008]

This feat will be removed in the next version.