[9.6-7] MUST: A server that sends a "close" connection option MUST initiate closure of the connection (see below) ...

[saviorand]

RFC 9112 Requirement

Section: 9.6-7 Keyword: MUST

A server that sends a "close" connection option MUST initiate closure of the connection (see below) after it sends the response containing the "close" connection option. The server MUST NOT process any further requests received on that connection.¶

Reference: https://www.rfc-editor.org/rfc/rfc9112.html#section-9.6-7