doc: add example for piping ReadableStream

When piping a `ReadableStream` created from an `Iterable` into a
`WritableStream`, the sequence of objects in the `Iterable` must
consist of either `Buffer`s, `TypedArray`s, or `DataView`s.

Re: nodejs#56297

doc/api/webstreams.md

@@ -436,6 +436,39 @@ async function* asyncIterableGenerator() {
 })();
 ```
 
+To pipe the resulting {ReadableStream} into a {WritableStream} the {Iterable}
+should yield a sequence of {Buffer}, {TypedArray}, or {DataView} objects.
+
+```mjs
+import { ReadableStream } from 'node:stream/web';
+import { Buffer } from 'node:buffer';
+
+async function* asyncIterableGenerator() {
+  yield Buffer.from('a');
+  yield Buffer.from('b');
+  yield Buffer.from('c');
+}
+
+const stream = ReadableStream.from(asyncIterableGenerator());
+
+stream.pipeTo(createWritableStreamSomehow());
+```
+
+```cjs
+const { ReadableStream } = require('node:stream/web');
+const { Buffer } = require('node:buffer');
+
+async function* asyncIterableGenerator() {
+  yield Buffer.from('a');
+  yield Buffer.from('b');
+  yield Buffer.from('c');
+}
+
+const stream = ReadableStream.from(asyncIterableGenerator());
+
+stream.pipeTo(createWritableStreamSomehow());
+```
+
 ### Class: `ReadableStreamDefaultReader`
 
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