function newReadableStream(underlyingSource) {
  if (USE_NATIVE_IMPLEMENTATION === 'true' ||
      (USE_NATIVE_IMPLEMENTATION === 'detect' && goog.global.ReadableStream)) {
    return liteNativeImpl.newReadableStream(underlyingSource);
  } else {
    return liteImpl.newReadableStream(underlyingSource);
  }
}
Creates and returns a new ReadableStream.

The underlying source should only have a start() method, and no other
properties.
@param {!ReadableStreamUnderlyingSource<T>} underlyingSource
@return {!ReadableStream<T>}
@suppress {strictMissingProperties}
@template T