docs(protocol): write about recv messages in wrac

src/app/protocol/wrac/page.tsx

@@ -26,7 +26,25 @@ export default function Wrac() {
         <Text>
           WRAC (WebSocket Real Address Chat) is a community-made successor to
           RAC that uses WebSockets instead of TCP. It uses the same requests as
-          RAC, but you should send data in binary format.
+          RAC, but you should send data in binary format. Also, you can use the
+          same connection multiple times, what differs from the usual RAC, where
+          you had to connect the server each time you made some request. That
+          causes some differences in the receiving messages.
+        </Text>
+        <Title id={"receiving-messages"}>Receiving messages</Title>
+        <Text>
+          As the connection now can be keep-alive, and the websocket uses messages
+          for transactions, we can't just do the same as we did in RAC to get the messages.
+        </Text>
+        <Text>
+          Now, to use those packets (<InlineCode>0x01</InlineCode> for normal reading and <InlineCode>0x02</InlineCode> for chunked reading),
+          we need to let the server know that we want to use them, and not send
+          messages (the same packet-ids). The way how to do this is just add the byte <InlineCode>0x00</InlineCode> to the start
+          of packets. For example: <InlineCode>0x00</InlineCode> <InlineCode>0x01</InlineCode> for normal reading.
+        </Text>
+        <Text>
+          This way we can separate the packets that receive data from the packet that receives the total size.
+          In this sense, WRAC solves a big problem with usual RAC.
         </Text>
         <Footer />
       </main>