Constant toad_msg::opt::known::no_repeat::IF_NONE_MATCH

pub const IF_NONE_MATCH: OptNumber;

If-None-Match

generated from RFC7252 section 5.10.8.2

The If-None-Match Option MAY be used to make a request conditional on the nonexistence of the target resource. If-None-Match is useful for resource creation requests, such as PUT requests, as a means for protecting against accidental overwrites when multiple clients are acting in parallel on the same resource. The If-None-Match Option carries no value.

If the target resource does exist, then the condition is not fulfilled.

(It is not very useful to combine If-Match and If-None-Match options in one request, because the condition will then never be fulfilled.)