(@dezlov, it seems that your comment was removed from this PR on rebase, so I will replicate here:)

@dezlov:
I didn't have chance to verify that converters above actually work with PHP, but I've noticed few other problems.

1. Typo in Cookies.withConverter(...), it is called with 2 x write properties. (fixed in latest version)
2. Usage of setrawcookie() is missing as documented in Optional encoder function, in addition to decoder (converter) #70 (comment), it's quite important:

In PHP, use setrawcookie() instead of setcookie():

setrawcookie($name, rawurlencode($value));

I didn't have chance to verify that converters above actually work with PHP

I didn't tested it either. It is just a reference documentation to workaround server-side incompatibilities based in PHP docs and Tomcat's source code.

In PHP, use setrawcookie() instead of setcookie():

I will add that

@dezlov, added on 16a8b8c.