# Functions
CreatePragma to create new instance of CacheControl from request.
FormatTime format time.
ParseTime parse time.
# Constants
HeaderCacheControl as in https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Cache-Control.
HeaderExpires as in https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Expires.
HeaderIfModifiedSince as in https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/If-Modified-Since.
HeaderLastModified as in https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Last-Modified.