Given a "$type": "foo.Bar" sealed trait discriminator, Custom Keys's @key annotation allows you to replace the right hand side "foo.Bar" of a particular case class by annotating the case class, but it does not allow you to replace to left hand side "$type" string with something else.

This ticket is to implement the ability for a user to replace $type" with some other string, by annotating the sealed trait itself with @key("myType") annotation that would replace "$type" with "myType" for all sub-classes of the sealed trait.

To incentivize contribution, I'm putting a 500USD bounty on resolving this ticket. This is payable via bank transfer, and at my discretion in case of ambiguity.