Add http3Only and dedicated parameters to "obtain a connection"

For WebTransport, see: w3c/webtransport#128.

fetch.bs

@@ -89,6 +89,24 @@ url:https://tools.ietf.org/html/draft-ietf-httpbis-header-structure#section-4.2;
         "href": "https://tools.ietf.org/html/draft-ietf-httpbis-header-structure",
         "publisher": "IETF",
         "title": "Structured Field Values for HTTP"
+    },
+    "HTTP3": {
+        "authors": ["M. Bishop, Ed."],
+        "href": "https://tools.ietf.org/html/draft-ietf-quic-http",
+        "publisher": "IETF",
+        "title": "Hypertext Transfer Protocol Version 3 (HTTP/3)"
+    },
+    "WEBTRANSPORT-HTTP3": {
+        "authors": ["V. Vasiliev"],
+        "href": "https://tools.ietf.org/html/draft-ietf-webtrans-http3",
+        "publisher": "IETF",
+        "title": "WebTransport over HTTP/3"
+    },
+    "HTTP3-DATAGRAM": {
+        "authors": ["David Schinazi", "Lucas Pardue"],
+        "href": "https://tools.ietf.org/html/draft-ietf-masque-h3-datagram",
+        "publisher": "IETF",
+        "title": "Using QUIC Datagrams with HTTP/3"
     }
 }
 </pre>
@@ -2121,12 +2139,27 @@ identified by a <b>key</b> (a <a>network partition key</a>), an <b>origin</b> (a
 <a for=/>origin</a>), and <b>credentials</b> (a boolean).
 
 <p>To <dfn export id=concept-connection-obtain>obtain a connection</dfn>, given a <var>key</var>,
-<var>origin</var>, and <var>credentials</var>, run these steps:
+<var>origin</var>, <var>credentials</var>, an optional boolean
+<dfn export for="obtain a connection"><var>http3Only</var></dfn> (default: false), and an optional
+boolean <dfn export for="obtain a connection"><var>dedicated</var></dfn> (default: false), run these
+steps:
+<!-- http3Only and dedicated have been added for WebTransport -->
 
 <ol>
- <li><p>If the user agent's <a>connection pool</a> contains a <a>connection</a> whose <b>key</b> is
- <var>key</var>, <b>origin</b> is <var>origin</var>, and <b>credentials</b> is
- <var>credentials</var>, then return that <a>connection</a>.
+ <li>
+  <p>If <var>dedicated</var> is false, then:
+
+  <ol>
+   <li><p>Let <var>connections</var> be a set of <a>connections</a> in the user agent's
+   <a>connection pool</a> each of whose <b>key</b> is <var>key</var>, <b>origin</b> is
+   <var>origin</var>, and <b>credentials</b> is <var>credentials</var>.
+
+   <li><p>If <var>connections</var> is not empty and <var>http3Only</var> is false, then return
+   one of <var>connections</var>.
+
+   <li><p>If there is an HTTP/3 <a>connection</a> in <var>connections</var>, then return that
+   <a>connection</a>.
+  </ol>
 
  <li><p>Let <var>connection</var> be null.
 
@@ -2139,6 +2172,12 @@ identified by a <b>key</b> (a <a>network partition key</a>), an <b>origin</b> (a
     <var>origin</var>. [[!HTTP]] [[!HTTP-SEMANTICS]] [[!HTTP-COND]] [[!HTTP-CACHING]] [[!HTTP-AUTH]]
     [[!TLS]]
 
+    <p>If <var>http3Only</var> is true, then establish an HTTP/3 connection. [[!HTTP3]]
+
+    <p>When establishing an HTTP/3 connection, include SETTINGS_ENABLE_WEBTRANSPORT with a value of
+    1 and H3_DATAGRAM with a value of 1 in the initial SETTINGS frame. [[!WEBTRANSPORT-HTTP3]]
+    [[!HTTP3-DATAGRAM]]
+
     <p>If <var>credentials</var> is false, then do <em>not</em> send a TLS client certificate.
 
     <p>If establishing a connection does not succeed (e.g., a DNS, TCP, or TLS error), then return
@@ -2154,9 +2193,9 @@ identified by a <b>key</b> (a <a>network partition key</a>), an <b>origin</b> (a
    <li><p>Return failure.
   </ol>
 
- <li><p>Add <var>connection</var> to the user agent's <a>connection pool</a> with <b>key</b> being
- <var>key</var>, <b>origin</b> being <var>origin</var>, and <b>credentials</b> being
- <var>credentials</var>.
+ <li><p>If <var>dedicated</var> is false, then add <var>connection</var> to the user agent's
+ <a>connection pool</a> with <b>key</b> being <var>key</var>, <b>origin</b> being <var>origin</var>,
+ and <b>credentials</b> being <var>credentials</var>.
 
  <li><p>Return <var>connection</var>.
 </ol>