feat(store): state subscription primitives (#528)

packages/utils/src/function/identity.ts

@@ -0,0 +1,3 @@
+export function identity<T>(value: T): T {
+  return value;
+}

packages/utils/src/function/index.ts

@@ -1,3 +1,4 @@
 export { composeCallbacks } from './compose-callbacks';
+export { identity } from './identity';
 export { noop } from './noop';
 export { tryCatch } from './try-catch';