The ModifiedMatcher
class is used to check if the request headers contain the If-Modified-Since
header and if the
last modified date is greater than the date in the header.
Additionally, it can check if the request headers contain the If-Unmodified-Since
header and if the last modified date
is less than or equal to the date in the header.
Check if the resource has been modified since the date specified in the If-Modified-Since
header.
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Check if the resource has not been modified since the date specified in the If-Unmodified-Since
header.
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