Add UnsupportedOsPlatform(browser) to more synchronous http apis (#43102)

src/libraries/System.Net.Http/ref/System.Net.Http.cs

@@ -90,9 +90,13 @@ public partial class HttpClient : System.Net.Http.HttpMessageInvoker
         public System.Threading.Tasks.Task<System.Net.Http.HttpResponseMessage> PutAsync(string? requestUri, System.Net.Http.HttpContent content, System.Threading.CancellationToken cancellationToken) { throw null; }
         public System.Threading.Tasks.Task<System.Net.Http.HttpResponseMessage> PutAsync(System.Uri? requestUri, System.Net.Http.HttpContent content) { throw null; }
         public System.Threading.Tasks.Task<System.Net.Http.HttpResponseMessage> PutAsync(System.Uri? requestUri, System.Net.Http.HttpContent content, System.Threading.CancellationToken cancellationToken) { throw null; }
+        [System.Runtime.Versioning.UnsupportedOSPlatformAttribute("browser")]
         public System.Net.Http.HttpResponseMessage Send(System.Net.Http.HttpRequestMessage request) { throw null; }
+        [System.Runtime.Versioning.UnsupportedOSPlatformAttribute("browser")]
         public System.Net.Http.HttpResponseMessage Send(System.Net.Http.HttpRequestMessage request, System.Net.Http.HttpCompletionOption completionOption) { throw null; }
+        [System.Runtime.Versioning.UnsupportedOSPlatformAttribute("browser")]
         public System.Net.Http.HttpResponseMessage Send(System.Net.Http.HttpRequestMessage request, System.Net.Http.HttpCompletionOption completionOption, System.Threading.CancellationToken cancellationToken) { throw null; }
+        [System.Runtime.Versioning.UnsupportedOSPlatformAttribute("browser")]
         public override System.Net.Http.HttpResponseMessage Send(System.Net.Http.HttpRequestMessage request, System.Threading.CancellationToken cancellationToken) { throw null; }
         public System.Threading.Tasks.Task<System.Net.Http.HttpResponseMessage> SendAsync(System.Net.Http.HttpRequestMessage request) { throw null; }
         public System.Threading.Tasks.Task<System.Net.Http.HttpResponseMessage> SendAsync(System.Net.Http.HttpRequestMessage request, System.Net.Http.HttpCompletionOption completionOption) { throw null; }
@@ -195,6 +199,7 @@ public partial class HttpMessageInvoker : System.IDisposable
         public HttpMessageInvoker(System.Net.Http.HttpMessageHandler handler, bool disposeHandler) { }
         public void Dispose() { }
         protected virtual void Dispose(bool disposing) { }
+        [System.Runtime.Versioning.UnsupportedOSPlatformAttribute("browser")]
         public virtual System.Net.Http.HttpResponseMessage Send(System.Net.Http.HttpRequestMessage request, System.Threading.CancellationToken cancellationToken) { throw null; }
         public virtual System.Threading.Tasks.Task<System.Net.Http.HttpResponseMessage> SendAsync(System.Net.Http.HttpRequestMessage request, System.Threading.CancellationToken cancellationToken) { throw null; }
     }

src/libraries/System.Net.Http/src/System/Net/Http/HttpClient.cs

@@ -5,6 +5,7 @@
 using System.Diagnostics.CodeAnalysis;
 using System.IO;
 using System.Net.Http.Headers;
+using System.Runtime.Versioning;
 using System.Threading;
 using System.Threading.Tasks;
 
@@ -439,15 +440,19 @@ public Task<HttpResponseMessage> PatchAsync(Uri? requestUri, HttpContent content
 
         #region Advanced Send Overloads
 
+        [UnsupportedOSPlatform("browser")]
         public HttpResponseMessage Send(HttpRequestMessage request) =>
             Send(request, DefaultCompletionOption, cancellationToken: default);
 
+        [UnsupportedOSPlatform("browser")]
         public HttpResponseMessage Send(HttpRequestMessage request, HttpCompletionOption completionOption) =>
             Send(request, completionOption, cancellationToken: default);
 
+        [UnsupportedOSPlatform("browser")]
         public override HttpResponseMessage Send(HttpRequestMessage request, CancellationToken cancellationToken) =>
             Send(request, DefaultCompletionOption, cancellationToken);
 
+        [UnsupportedOSPlatform("browser")]
         public HttpResponseMessage Send(HttpRequestMessage request, HttpCompletionOption completionOption, CancellationToken cancellationToken)
         {
             // Called outside of async state machine to propagate certain exception even without awaiting the returned task.

src/libraries/System.Net.Http/src/System/Net/Http/HttpMessageInvoker.cs

@@ -3,6 +3,7 @@
 
 using System.IO;
 using System.Net.Http.Headers;
+using System.Runtime.Versioning;
 using System.Threading;
 using System.Threading.Tasks;
 
@@ -32,6 +33,7 @@ public HttpMessageInvoker(HttpMessageHandler handler, bool disposeHandler)
             _disposeHandler = disposeHandler;
         }
 
+        [UnsupportedOSPlatformAttribute("browser")]
         public virtual HttpResponseMessage Send(HttpRequestMessage request,
             CancellationToken cancellationToken)
         {