// array(2) {
// [0]=> string(6) "user:1"
// [1]=> string(6) "user:2"
// [2]=> string(6) "user:3"
// [3]=> string(6) "user:4"
// [4]=> string(6) "user:5"
// }
// Get users with tag <country:UK>
var_dump($MemcachedTags->getKeysByTag('country:UK'));
// array(2) {
// [0]=> string(6) "user:1"
// [1]=> string(6) "user:2"
// [2]=> string(6) "user:5"
// }
// Get users with tag <city:Petersburg> OR <city:Murmansk>
var_dump($MemcachedTags->getKeysByTags(['city:Petersburg', 'city:Murmansk'], MemcachedTags::COMPILATION_OR));
// array(2) {
// [0]=> string(6) "user:3"
// [1]=> string(6) "user:4"
// }
// Get users with tags <country:UK> AND <sex:m>
var_dump($MemcachedTags->getKeysByTags(['country:UK', 'sex:m'], MemcachedTags::COMPILATION_AND));
// array(3) {
// [0]=> string(6) "user:1"
// [1]=> string(6) "user:5"
// }
// Get users with tag <country:UK> AND WITHOUT <sex:m>
var_dump($MemcachedTags->getKeysByTags(['country:UK', 'sex:m'], MemcachedTags::COMPILATION_XOR));
// array(3) {
// [0]=> string(6) "user:2"
// }
