Trailblazer::Declarative
State
State is a minimalistic state handling object, similar to a hash with
additional "inheritance" logic via State#copy. Every field in state
can have a specific copying strategy, ranging from simply referencing the
original object to subclassing.
state = Declarative.State(key: ["value", ...])
state.add!
state.update!
state.get
state.copy # inheritance