Move LifecycleDisposable to core-util.

core-util/src/main/java/org/signal/core/util/concurrent/LifecycleDisposable.kt

@@ -0,0 +1,46 @@
+package org.signal.core.util.concurrent
+
+import androidx.lifecycle.DefaultLifecycleObserver
+import androidx.lifecycle.Lifecycle
+import androidx.lifecycle.LifecycleOwner
+import io.reactivex.rxjava3.disposables.CompositeDisposable
+import io.reactivex.rxjava3.disposables.Disposable
+
+/**
+ * A lifecycle-aware [Disposable] that, after being bound to a lifecycle, will automatically dispose all contained disposables at the proper time.
+ */
+class LifecycleDisposable : DefaultLifecycleObserver {
+  val disposables: CompositeDisposable = CompositeDisposable()
+
+  fun bindTo(lifecycleOwner: LifecycleOwner): LifecycleDisposable {
+    return bindTo(lifecycleOwner.lifecycle)
+  }
+
+  fun bindTo(lifecycle: Lifecycle): LifecycleDisposable {
+    lifecycle.addObserver(this)
+    return this
+  }
+
+  fun add(disposable: Disposable): LifecycleDisposable {
+    disposables.add(disposable)
+    return this
+  }
+
+  fun addAll(vararg disposable: Disposable): LifecycleDisposable {
+    disposables.addAll(*disposable)
+    return this
+  }
+
+  fun clear() {
+    disposables.clear()
+  }
+
+  override fun onDestroy(owner: LifecycleOwner) {
+    owner.lifecycle.removeObserver(this)
+    disposables.clear()
+  }
+
+  operator fun plusAssign(disposable: Disposable) {
+    add(disposable)
+  }
+}