Add anticipatedConcurrentIncoming[Bi/Uni]directionalStreams attributes & constructor arg

index.bs

@@ -606,6 +606,9 @@ interface WebTransport {
   readonly attribute Promise<undefined> ready;
   readonly attribute WebTransportReliabilityMode reliability;
   readonly attribute WebTransportCongestionControl congestionControl;
+  [EnforceRange] attribute unsigned short? anticipatedConcurrentIncomingUnidirectionalStreams;
+  [EnforceRange] attribute unsigned short? anticipatedConcurrentIncomingBidirectionalStreams;
+
   readonly attribute Promise<WebTransportCloseInfo> closed;
   readonly attribute Promise<undefined> draining;
   undefined close(optional WebTransportCloseInfo closeInfo = {});
@@ -688,6 +691,16 @@ A {{WebTransport}} object has the following internal slots.
    throughput or low latency was requested by the application and satisfied
    by the user agent, or `"default"`.
   </tr>
+  <tr>
+   <td><dfn>`[[AnticipatedConcurrentIncomingUnidirectionalStreams]]`</dsfn>
+   <td class="non-normative">The number of concurrently open
+   [=incoming unidirectional=] streams the application anticipates the server creating, or null.
+  </tr>
+  <tr>
+   <td><dfn>`[[AnticipatedConcurrentIncomingBidirectionalStreams]]`</dfn>
+   <td class="non-normative">The number of concurrently open
+   [=bidirectional=] streams the application anticipates the server creating, or null.
+  </tr>
   <tr>
    <td><dfn>`[[Closed]]`</dfn>
    <td class="non-normative">A promise fulfilled when the associated {{WebTransport}} object is
@@ -734,6 +747,10 @@ agent MUST run the following steps:
    congestion control algorithms that optimize for |congestionControl|, as allowed by
    [[!RFC9002]] [Section 7](https://www.rfc-editor.org/rfc/rfc9002#section-7),
    then set |congestionControl| to `"default"`.
+1. Let |anticipatedConcurrentIncomingUnidirectionalStreams| be {{WebTransport/constructor(url, options)/options}}'s
+   {{WebTransportOptions/anticipatedConcurrentIncomingUnidirectionalStreams}}.
+1. Let |anticipatedConcurrentIncomingBidirectionalStreams| be {{WebTransport/constructor(url, options)/options}}'s
+   {{WebTransportOptions/anticipatedConcurrentIncomingBidirectionalStreams}}.
 1. Let |incomingDatagrams| be a [=new=] {{ReadableStream}}.
 1. Let |outgoingDatagrams| be a [=new=] {{WritableStream}}.
 1. Let |datagrams| be the result of [=WebTransportDatagramDuplexStream/creating=] a
@@ -756,6 +773,10 @@ agent MUST run the following steps:
     :: "pending"
     : {{[[CongestionControl]]}}
     :: |congestionControl|
+    : {{[[AnticipatedConcurrentIncomingUnidirectionalStreams]]}}
+    :: |anticipatedConcurrentIncomingUnidirectionalStreams|
+    : {{[[AnticipatedConcurrentIncomingBidirectionalStreams]]}}
+    :: |anticipatedConcurrentIncomingBidirectionalStreams|
     : {{[[Closed]]}}
     :: a new promise
     : {{[[Draining]]}}
@@ -954,6 +975,34 @@ these steps.
 :: Returns true if the user agent supports [=WebTransport sessions=] over exclusively reliable
    [=connections=], otherwise false.
 
+: <dfn for="WebTransport" attribute>anticipatedConcurrentIncomingUnidirectionalStreams</dfn>
+:: Optionally lets an application specify the number of concurrently open
+   [=incoming unidirectional=] streams it anticipates the server creating.
+   If not null, the user agent SHOULD attempt to reduce future round-trips by taking
+   {{[[AnticipatedConcurrentIncomingUnidirectionalStreams]]}} into consideration in its
+   negotiations with the server.
+
+   The getter steps are to return [=this=]'s {{[[AnticipatedConcurrentIncomingUnidirectionalStreams]]}}.
+
+   The setter steps, given |value|, are to set [=this=]'s
+   {{[[AnticipatedConcurrentIncomingUnidirectionalStreams]]}} to |value|.
+
+: <dfn for="WebTransport" attribute>anticipatedConcurrentIncomingBidirectionalStreams</dfn>
+:: Optionally lets an application specify the number of concurrently open
+   [=bidirectional=] streams it anticipates the server creating.
+   If not null, the user agent SHOULD attempt to reduce future round-trips by taking
+   {{[[AnticipatedConcurrentIncomingBidirectionalStreams]]}} into consideration in its
+   negotiations with the server.
+
+   The getter steps are to return [=this=]'s {{[[AnticipatedConcurrentIncomingBidirectionalStreams]]}}.
+
+   The setter steps, given |value|, are to set [=this=]'s
+   {{[[AnticipatedConcurrentIncomingBidirectionalStreams]]}} to |value|.
+
+   Note: Setting {{anticipatedConcurrentIncomingUnidirectionalStreams}} or
+   {{anticipatedConcurrentIncomingBidirectionalStreams}} does not guarantee
+   the application will receive the number of streams it anticipates.
+
 ## Methods ##  {#webtransport-methods}
 
 <div algorithm>
@@ -1222,6 +1271,8 @@ dictionary WebTransportOptions {
   boolean requireUnreliable = false;
   sequence&lt;WebTransportHash&gt; serverCertificateHashes;
   WebTransportCongestionControl congestionControl = "default";
+  [EnforceRange] unsigned short? anticipatedConcurrentIncomingUnidirectionalStreams = null;
+  [EnforceRange] unsigned short? anticipatedConcurrentIncomingBidirectionalStreams = null;
 };
 
 enum WebTransportCongestionControl {
@@ -1267,6 +1318,20 @@ that determine how the [=WebTransport session=] is established and used.
      </p>
    </div>
 
+: <dfn for="WebTransportOptions" dict-member>anticipatedConcurrentIncomingUnidirectionalStreams</dfn>
+:: Optionally lets an application specify the number of concurrently open
+   [=incoming unidirectional=] streams it anticipates the server creating.
+   If not null, the user agent SHOULD attempt to reduce round-trips by taking
+   {{[[AnticipatedConcurrentIncomingUnidirectionalStreams]]}} into consideration in its
+   negotiations with the server.
+
+: <dfn for="WebTransportOptions" dict-member>anticipatedConcurrentIncomingBidirectionalStreams</dfn>
+:: Optionally lets an application specify the number of concurrently open
+   [=bidirectional=] streams it anticipates a server creating.
+   If not null, the user agent SHOULD attempt to reduce round-trips by taking
+   {{[[AnticipatedConcurrentIncomingBidirectionalStreams]]}} into consideration in its
+   negotiations with the server.
+
 <div algorithm>
 To <dfn>compute a certificate hash</dfn>, given a |certificate|, perform the following steps:
 1. Let |cert| be |certificate|, represented as a DER encoding of