The sink output.
The source input.
The property key. This key is used internally only, but should be namespaced to avoid conflict with third-party extensions.
The stored value, if found; otherwise null.
A future with an array of sink outputs.
A future with an array of source inputs.
The property key. This key is used internally only, but should be namespaced to avoid conflict with third-party extensions.
The property value. This can be any object that needs to be stored for future use.
The property key. This key is used internally only, but should be namespaced to avoid conflict with third-party extensions.
true if the value was removed; otherwise, false.