second round of suggested changes

src/Microsoft.Identity.Web/DownstreamWebApiSupport/DownstreamWebApi.cs

@@ -80,7 +80,6 @@ public async Task<HttpResponseMessage> CallWebApiForUserAsync(
                 effectiveOptions.TokenAcquisitionOptions)
                 .ConfigureAwait(false);
 
-            HttpResponseMessage response;
             using (HttpRequestMessage httpRequestMessage = new HttpRequestMessage(
                 effectiveOptions.HttpMethod,
                 apiUrl))
@@ -93,10 +92,8 @@ public async Task<HttpResponseMessage> CallWebApiForUserAsync(
                 httpRequestMessage.Headers.Add(
                     Constants.Authorization,
                     authResult.CreateAuthorizationHeader());
-                response = await _httpClient.SendAsync(httpRequestMessage).ConfigureAwait(false);
+                return await _httpClient.SendAsync(httpRequestMessage).ConfigureAwait(false);
             }
-
-            return response;
         }
 
         /// <inheritdoc/>

src/Microsoft.Identity.Web/DownstreamWebApiSupport/DownstreamWebApiOptions.cs

@@ -1,6 +1,7 @@
 // Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT License.
 
+using System;
 using System.Net.Http;
 
 namespace Microsoft.Identity.Web
@@ -9,7 +10,7 @@ namespace Microsoft.Identity.Web
     /// Options passed-in to call downstream web APIs. To call Microsoft Graph, see rather
     /// <c>MicrosoftGraphOptions</c> in the <c>Microsoft.Identity.Web.MicrosoftGraph</c> assembly.
     /// </summary>
-    public class DownstreamWebApiOptions
+    public class DownstreamWebApiOptions : ICloneable
     {
         /// <summary>
         /// Base URL for the called downstream web API. For instance <c>"https://graph.microsoft.com/beta/".</c>.
@@ -97,5 +98,14 @@ public string[] GetScopes()
         {
             return string.IsNullOrWhiteSpace(Scopes) ? new string[0] : Scopes.Split(' ');
         }
+
+        /// <summary>
+        /// Clone the options (to be able to override them).
+        /// </summary>
+        /// <returns>A clone of the options.</returns>
+        object ICloneable.Clone()
+        {
+            return Clone();
+        }
     }
 }

src/Microsoft.Identity.Web/DownstreamWebApiSupport/IDownstreamWebApi.cs

@@ -54,9 +54,9 @@ public Task<HttpResponseMessage> CallWebApiForUserAsync(
         /// <example>
         /// A list method that returns an IEnumerable&lt;MyItem&gt;&gt;.
         /// <code>
-        /// public async Task&lt;IEnumerable&lt;MyItem&gt;&gt; GetAsync()
+        /// public Task&lt;IEnumerable&lt;MyItem&gt;&gt; GetAsync()
         /// {
-        ///  return await _downstreamWebApi.CallWebApiForUserAsync&lt;object, IEnumerable&lt;MyItem&gt;&gt;(
+        ///  return _downstreamWebApi.CallWebApiForUserAsync&lt;object, IEnumerable&lt;MyItem&gt;&gt;(
         ///         ServiceName,
         ///         null,
         ///         options =>
@@ -68,9 +68,9 @@ public Task<HttpResponseMessage> CallWebApiForUserAsync(
         ///
         /// Example of editing.
         /// <code>
-        /// public async Task&lt;MyItem&gt; EditAsync(MyItem myItem)
+        /// public Task&lt;MyItem&gt; EditAsync(MyItem myItem)
         /// {
-        ///   return await _downstreamWebApi.CallWebApiForUserAsync&lt;MyItem, MyItem&gt;(
+        ///   return _downstreamWebApi.CallWebApiForUserAsync&lt;MyItem, MyItem&gt;(
         ///         ServiceName,
         ///         nyItem,
         ///         options =>

src/Microsoft.Identity.Web/IncrementalConsentAndConditionalAccessHelper.cs

@@ -60,17 +60,17 @@ public static AuthenticationProperties BuildAuthenticationProperties(
             scopes ??= new string[0];
             var properties = new AuthenticationProperties();
 
-            // Set the scopes, including the scopes that ADAL.NET / MSAL.NET need for the token cache
+            // Set the scopes, including the scopes that MSAL.NET needs for the token cache
             string[] additionalBuiltInScopes =
             {
                  OidcConstants.ScopeOpenId,
                  OidcConstants.ScopeOfflineAccess,
                  OidcConstants.ScopeProfile,
             };
 
-            properties.SetParameter<ICollection<string>>(
-                OpenIdConnectParameterNames.Scope,
-                scopes.Union(additionalBuiltInScopes).ToList());
+            HashSet<string> oidcParams = new HashSet<string>(scopes);
+            oidcParams.UnionWith(additionalBuiltInScopes);
+            properties.SetParameter(OpenIdConnectParameterNames.Scope, oidcParams);
 
             // Attempts to set the login_hint to avoid the logged-in user to be presented with an account selection dialog
             var loginHint = user.GetLoginHint();