Assertion: request's header field | /r/ObjectUse | used with method
Facets:
Source sentences:
text: The If-Modified-Since request-header field is used with a method to make it conditional: if the requested variant has not been modified since the time specified in this field, an entity will not be returned from the server; instead, a 304 (not modified) response will be returned without any message-body.
text: The If-Unmodified-Since request-header field is used with a method to make it conditional.