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// Copyright (c) 2015, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
import 'dart:async';
/// Simple delegating wrapper around a [StreamSink].
/// Subclasses can override individual methods, or use this to expose only the
/// [StreamSink] methods of a subclass.
class DelegatingStreamSink<T> implements StreamSink<T> {
final StreamSink _sink;
Future get done => _sink.done;
/// Create delegating sink forwarding calls to [sink].
DelegatingStreamSink(StreamSink<T> sink) : _sink = sink;
/// Creates a wrapper that coerces the type of [sink].
/// Unlike [new StreamSink], this only requires its argument to be an instance
/// of `StreamSink`, not `StreamSink<T>`. This means that calls to [add] may
/// throw a [CastError] if the argument type doesn't match the reified type of
/// [sink].
static StreamSink<T> typed<T>(StreamSink sink) =>
sink is StreamSink<T> ? sink : DelegatingStreamSink._(sink);
void add(T data) {
void addError(error, [StackTrace stackTrace]) {
_sink.addError(error, stackTrace);
Future addStream(Stream<T> stream) => _sink.addStream(stream);
Future close() => _sink.close();