quic-api: first take

en/SUMMARY.md

@@ -26,6 +26,7 @@
     * [0-RTT](quic-0rtt.md)
     * [Spin Bit](quic-spinbit.md)
     * [User space](quic-userspace.md)
+    * [API](quic-api.md)
 * [HTTP/3](h3.md)
     * [HTTPS:// URLs](h3-https.md)
     * [Bootstrap with Alt-svc](h3-altsvc.md)

en/quic-api.md

@@ -0,0 +1,17 @@
+# API
+
+One of the success factors for regular TCP and programs using that, is the
+standardized socket API. It has well defined functionality and using this API
+you can move programs between many different operating systems as TCP works
+the same.
+
+QUIC is not there. There is no standard API for QUIC.
+
+With QUIC, you need to pick one of the existing library implementations and
+stick with its API. It makes applications "locked in" to a single library to
+some extent. Changing to another library means another API and that might
+involve a lot of work.
+
+Also, since QUIC is typically implemented in user-space, it can't easily just
+extend the socket API or appear similar to how existing TCP and UDP
+functionality do. Using QUIC will mean using another API than the socket API.