我应该指定 "Vary: If-None-Match, If-Modified-Since" 吗？
Should I specify "Vary: If-None-Match, If-Modified-Since"?
The "Vary" header field in a response describes what parts of a
request message, aside from the method, Host header field, and
request target, might influence the origin server's process for
selecting and representing this response.
没有
An origin server SHOULD send a Vary header field when its algorithm
for selecting a representation varies based on aspects of the request
message other than the method and request target
在这种情况下，表示不是由那些 headers 的值决定的。它们用于决定是否应发送 body。
提示：
For example, there is no
need to send the Authorization field name in Vary because reuse
across users is constrained by the field definition
同样适用于条件请求字段。
The "Vary" header field in a response describes what parts of a
request message, aside from the method, Host header field, and
request target, might influence the origin server's process for
selecting and representing this response.
没有
An origin server SHOULD send a Vary header field when its algorithm for selecting a representation varies based on aspects of the request message other than the method and request target
在这种情况下，表示不是由那些 headers 的值决定的。它们用于决定是否应发送 body。
提示：
For example, there is no need to send the Authorization field name in Vary because reuse across users is constrained by the field definition
同样适用于条件请求字段。