UI 자동화를 위해 바인딩 기능 구현

- 유니티 에셋 인증 오류로 meta 재생성

Packages/com.unity.inputsystem/InputSystem/Utilities/Observables/SelectObservable.cs

@@ -0,0 +1,48 @@
+using System;
+
+namespace UnityEngine.InputSystem.LowLevel
+{
+    internal class SelectObservable<TSource, TResult> : IObservable<TResult>
+    {
+        private readonly IObservable<TSource> m_Source;
+        private readonly Func<TSource, TResult> m_Filter;
+
+        public SelectObservable(IObservable<TSource> source, Func<TSource, TResult> filter)
+        {
+            m_Source = source;
+            m_Filter = filter;
+        }
+
+        public IDisposable Subscribe(IObserver<TResult> observer)
+        {
+            return m_Source.Subscribe(new Select(this, observer));
+        }
+
+        private class Select : IObserver<TSource>
+        {
+            private SelectObservable<TSource, TResult> m_Observable;
+            private readonly IObserver<TResult> m_Observer;
+
+            public Select(SelectObservable<TSource, TResult> observable, IObserver<TResult> observer)
+            {
+                m_Observable = observable;
+                m_Observer = observer;
+            }
+
+            public void OnCompleted()
+            {
+            }
+
+            public void OnError(Exception error)
+            {
+                Debug.LogException(error);
+            }
+
+            public void OnNext(TSource evt)
+            {
+                var result = m_Observable.m_Filter(evt);
+                m_Observer.OnNext(result);
+            }
+        }
+    }
+}