doc: documentation should mention that maxFreeSockets is per host

[snytkine]

📗 API Reference Docs Problem

• Version: ✍️16

• Platform: ✍️MacOS

• Subsystem: ✍️http

Location

Section of the site where the content exists

Affected URL(s):

• https://nodejs.org/api/http.html#http_new_agent_options

Description

Concise explanation of the problem

✍️
Currently documentation says:
maxFreeSockets Maximum number of sockets to leave open in a free state.
But after lookin at the source code in _http_agent.js it looks to me that maxFreeSockets is the maximum number of free sockets per host, similar how maxSockets number is per host.

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  submit a pull request.

[Samjin]

What is the difference between using maxSockets vs maxFreeSockets then?