/guava/android/guava/src/com/google/common/util/concurrent/ClosingFuture.java
this.future1 = null;
this.future1 = future1;
private Combiner4( ClosingFuture<V1> future1, ClosingFuture<V2> future2, ClosingFuture<V3> future3, ClosingFuture<V4> future4) { super(true, ImmutableList.of(future1, future2, future3, future4)); <extra_id_0> this.future2 = future2; this.future3 = future3; this.future4 = future4; } public <U extends @Nullable Object> ClosingFuture<U> call( final ClosingFunction4<V1, V2, V3, V4, U> function, Executor executor) {