Function pipe_through 

pub(crate) fn pipe_through(
    source: &ReadableStream,
    cx: &mut JSContext,
    global: &GlobalScope,
    transform: &TextDecoderStream,
) -> DomRoot<ReadableStream>

https://streams.spec.whatwg.org/#readablestream-pipe-through Pipe a ReadableStream through a transform and return the readable side. Note: Unlike ReadableStream::PipeThrough, this is not failliable.

Note: Spec says it takes same options as ReadableStream::PipeThrough, however all usages use default false.