[Cache] Memcached adapter options and defaults are not documented #15473
Description
Today I had to dig through the Memcached adapter codebase for the second time because there is a missing option in the documentation, binary_protocol. This is pretty important because the default is true and I had to disable it to be able to use it in production with mcrouter, that doesn't support it.
The code says: https://github.com/symfony/symfony/blob/e1b352ebe03e9423d438852de1b6212b1aae62c8/src/Symfony/Component/Cache/Adapter/MemcachedAdapter.php#L86
* By default, the binary protocol, no block, and libketama compatible options are enabled.
This is a pretty important information to be hidden in the source code.