fix Net Core 3.0，Dashboard Can't Load Js And Css. (#407)

src/DotNetCore.CAP/Dashboard/CombinedResourceDispatcher.cs

@@ -2,6 +2,7 @@
 // Licensed under the MIT License. See License.txt in the project root for license information.
 
 using System.Reflection;
+using System.Threading.Tasks;
 
 namespace DotNetCore.CAP.Dashboard
 {
@@ -22,14 +23,14 @@ namespace DotNetCore.CAP.Dashboard
             _resourceNames = resourceNames;
         }
 
-        protected override void WriteResponse(DashboardResponse response)
+        protected override async Task WriteResponse(DashboardResponse response)
         {
             foreach (var resourceName in _resourceNames)
             {
-                WriteResource(
+               await WriteResource(
                     response,
                     _assembly,
-                    $"{_baseNamespace}.{resourceName}");
+                    $"{_baseNamespace}.{resourceName}").ConfigureAwait(false);
             }
         }
     }

src/DotNetCore.CAP/Dashboard/EmbeddedResourceDispatcher.cs

@@ -30,22 +30,21 @@ namespace DotNetCore.CAP.Dashboard
             }
         }
 
-        public Task Dispatch(DashboardContext context)
+        public async Task Dispatch(DashboardContext context)
         {
             context.Response.ContentType = _contentType;
             context.Response.SetExpire(DateTimeOffset.Now.AddYears(1));
 
-            WriteResponse(context.Response);
+            await WriteResponse(context.Response).ConfigureAwait(false);
 
-            return Task.FromResult(true);
         }
 
-        protected virtual void WriteResponse(DashboardResponse response)
+        protected virtual Task WriteResponse(DashboardResponse response)
         {
-            WriteResource(response, _assembly, _resourceName);
+            return WriteResource(response, _assembly, _resourceName);
         }
 
-        protected void WriteResource(DashboardResponse response, Assembly assembly, string resourceName)
+        protected async Task WriteResource(DashboardResponse response, Assembly assembly, string resourceName)
         {
             using (var inputStream = assembly.GetManifestResourceStream(resourceName))
             {
@@ -55,7 +54,7 @@ namespace DotNetCore.CAP.Dashboard
                         $@"Resource with name {resourceName} not found in assembly {assembly}.");
                 }
 
-                inputStream.CopyTo(response.Body);
+                await inputStream.CopyToAsync(response.Body).ConfigureAwait(false);
             }
         }
     }