nl_tokens: ReadableStream API exposed for controllers .
pl_tokens: function ReadableStreamAddReadIntoRequest ( stream ) { assert ( IsReadableStreamBYOBReader ( stream . _reader ) === <mask> ) ; assert ( stream . _state === 'readable' || stream . _state === 'closed' ) ; const promise = new Promise ( ( resolve , reject ) => { const readIntoRequest = { _resolve : resolve , _reject : reject } ; stream . _reader . _readIntoRequests . push ( readIntoRequest ) ; } ) ; return promise ; }