1  var Stream = require('stream');
 2  if (process.env.READABLE_STREAM === 'disable' && Stream) {
 3    module.exports = Stream.Readable;
 4    Object.assign(module.exports, Stream);
 5    module.exports.Stream = Stream;
 6  } else {
 7    exports = module.exports = require('./lib/_stream_readable.js');
 8    exports.Stream = Stream || exports;
 9    exports.Readable = exports;
10    exports.Writable = require('./lib/_stream_writable.js');
11    exports.Duplex = require('./lib/_stream_duplex.js');
12    exports.Transform = require('./lib/_stream_transform.js');
13    exports.PassThrough = require('./lib/_stream_passthrough.js');
14    exports.finished = require('./lib/internal/streams/end-of-stream.js');
15    exports.pipeline = require('./lib/internal/streams/pipeline.js');
16  }