When you press the button, the following happens:

1. A text file is fetched as a ReadableStream and piped through a TextDecodeStream.
2. A file handle is created and exposed as a WritableStream.
3. The resulting decoded ReadableStream from step 1 is tee()ed into two ReadableStreams.
4. The first ReadableStream is streamed into a <pre> displayed on the screen.
5. The second ReadableStream is…
   • piped through an uppercase TransformStream,
   • then piped through a TextEncoderStream,
   • next piped through a CompressionStream,
   • and finally piped to the WritableStream from step 2.