pub struct EntityTag {
    pub weak: bool,
    // some fields omitted
}An entity tag, defined in RFC7232
An entity tag consists of a string enclosed by two literal double quotes.
Preceding the first double quote is an optional weakness indicator,
which always looks like W/. Examples for valid tags are "xyzzy" and W/"xyzzy".
entity-tag = [ weak ] opaque-tag
weak       = %x57.2F ; "W/", case-sensitive
opaque-tag = DQUOTE *etagc DQUOTE
etagc      = %x21 / %x23-7E / obs-text
           ; VCHAR except double quotes, plus obs-text
To check if two entity tags are equivalent in an application always use the strong_eq or
weak_eq methods based on the context of the Tag. Only use == to check if two tags are
identical.
The example below shows the results for a set of entity-tag pairs and
both the weak and strong comparison function results:
|  ETag 1   |  ETag 2   |  Strong Comparison  |  Weak Comparison  | 
 W/"1"  |  W/"1"  |  no match           |  match            | 
 W/"1"  |  W/"2"  |  no match           |  no match         | 
 W/"1"  |  "1"    |  no match           |  match            | 
 "1"    |  "1"    |  match              |  match            | 
Weakness indicator for the tag
 
                    
                Constructs a new EntityTag.
If the tag contains invalid characters.
Constructs a new weak EntityTag.
If the tag contains invalid characters.
Constructs a new strong EntityTag.
If the tag contains invalid characters.
Set the tag.
If the tag contains invalid characters.
For strong comparison two entity-tags are equivalent if both are not weak and their
opaque-tags match character-by-character.
For weak comparison two entity-tags are equivalent if their
opaque-tags match character-by-character, regardless of either or
both being tagged as "weak".
The inverse of EntityTag.strong_eq().
The inverse of EntityTag.weak_eq().
 
                
                This method tests for self and other values to be equal, and is used by ==. Read more
This method tests for !=.
Performs copy-assignment from source. Read more
The associated error which can be returned from parsing.
Parses a string s to return a value of this type. Read more
 Formats the value using the given formatter. Read more
Formats the value using the given formatter. Read more