title: NgRx Store with selector called twice
body: <p>I have simple store with selector</p>
  
  <pre><code>export const efficiency = createSelector(
      state =&gt; ({ ...state.dashboard}),
      dashboard =&gt; dashboard.efficiency
  );
  </code></pre>
  
  <p>And Store Subscription</p>
  
  <pre><code>this.store
    .pipe(
      select(efficiency )
    )
    .subscribe(state =&gt; {console.log(state)})
  </code></pre>
  
  <p>Due to some reason state subscription invoking <strong>twice</strong>.
  Also, Is their a way to restrict subscription invocation when selector initializes?</p>