Add documentation for System.Net.WebSockets APIs introduced in 2.x (#3555)

* Add documentation for System.Net.WebSockets APIs introduced in 2.x

* Apply suggestions from code review

Co-Authored-By: Maira Wenzel <[email protected]>

* Fix invalid cross references

Author: jozkee

xml/System.Net.WebSockets/ClientWebSocketOptions.xml

@@ -278,8 +278,8 @@
         <ReturnType>System.Net.Security.RemoteCertificateValidationCallback</ReturnType>
       </ReturnValue>
       <Docs>
-        <summary>To be added.</summary>
-        <value>To be added.</value>
+        <summary>Gets or sets the callback to validate a server certificate.</summary>
+        <value>A callback function to validate the server certificate.</value>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>

xml/System.Net.WebSockets/ValueWebSocketReceiveResult.xml

@@ -77,8 +77,8 @@
         <ReturnType>System.Int32</ReturnType>
       </ReturnValue>
       <Docs>
-        <summary>To be added.</summary>
-        <value>To be added.</value>
+        <summary>Gets the number of bytes that the <see cref="T:System.Net.WebSockets.WebSocket" /> received.</summary>
+        <value>The number of bytes that the <see cref="T:System.Net.WebSockets.WebSocket" /> received.</value>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -102,8 +102,9 @@
         <ReturnType>System.Boolean</ReturnType>
       </ReturnValue>
       <Docs>
-        <summary>To be added.</summary>
-        <value>To be added.</value>
+        <summary>Gets whether the message has been received completely.</summary>
+        <value>
+          <see langword="true"/> if the message was received completely; otherwise, <see langword="false"/>.</value>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -127,8 +128,8 @@
         <ReturnType>System.Net.WebSockets.WebSocketMessageType</ReturnType>
       </ReturnValue>
       <Docs>
-        <summary>To be added.</summary>
-        <value>To be added.</value>
+        <summary>Gets the type of the current message.</summary>
+        <value>One of the enumeration values that specifies if the current message is a UTF-8, binary, or close message.</value>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>

xml/System.Net.WebSockets/WebSocket.xml

@@ -683,10 +683,10 @@
         <Parameter Name="cancellationToken" Type="System.Threading.CancellationToken" Index="1" FrameworkAlternate="netcore-2.1;netcore-2.2;netcore-3.0;netstandard-2.1" />
       </Parameters>
       <Docs>
-        <param name="buffer">To be added.</param>
-        <param name="cancellationToken">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
+        <param name="buffer">The application buffer that is the storage location for the received data.</param>
+        <param name="cancellationToken">The cancellation token to use to cancel the receive operation.</param>
+        <summary>Receives data from the <see cref="T:System.Net.WebSockets.WebSocket" /> connection asynchronously.</summary>
+        <returns>The task object representing the asynchronous operation. The <see cref="P:System.Threading.Tasks.ValueTask`1.Result" /> property on the task object returns a <see cref="T:System.Net.WebSockets.ValueWebSocketReceiveResult" /> object that represents the received data.</returns>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -810,12 +810,13 @@
         <Parameter Name="cancellationToken" Type="System.Threading.CancellationToken" Index="3" FrameworkAlternate="netcore-2.1;netcore-2.2;netcore-3.0;netstandard-2.1" />
       </Parameters>
       <Docs>
-        <param name="buffer">To be added.</param>
-        <param name="messageType">To be added.</param>
-        <param name="endOfMessage">To be added.</param>
-        <param name="cancellationToken">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
+        <param name="buffer">The buffer to be sent over the connection.</param>
+        <param name="messageType">One of the enumeration values that indicates whether the application is sending a binary or text message.</param>
+        <param name="endOfMessage">
+          <see langword="true" /> to indicate the data in "buffer" is the last part of a message; otherwise, <see langword="false" />.</param>
+        <param name="cancellationToken">The cancellation token to use to cancel the send operation.</param>
+        <summary>Sends data over the <see cref="T:System.Net.WebSockets.WebSocket" /> connection asynchronously.</summary>
+        <returns>The task object representing the asynchronous operation.</returns>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>