dry-schema: Generating errors for unexpected keys in Hash

I would love to be able to define a schema which generated errors if it was given unexpected keys:

require 'dry/validation'

schema = Dry::Validation.Schema(strict: true) do
  hash? do
    required(:foo).filled(:int?)
    required(:bar).filled(:str?)
  end
end

outcome = schema.call(foo: 1, bar: "two", baz: 3.0)
p outcome.messages # => {:baz=>["is not allowed"]}

This is really important for defining a public JSON API where you want to reject invalid user input.