Added an option to disable the charset

Author: alexeyzimarev

src/RestSharp/Request/RequestContent.cs

@@ -117,6 +117,10 @@ void AddBody(bool hasPostParameters) {
             // we don't have parameters, only the body
             Content = bodyContent;
         }
+
+        if (_client.Options.DisableCharset) {
+            Content.Headers.ContentType.CharSet = "";
+        }
     }
 
     void AddPostParameters(ParametersCollection? postParameters) {

src/RestSharp/RestClientOptions.cs

@@ -51,6 +51,11 @@ public RestClientOptions(string baseUrl) : this(new Uri(Ensure.NotEmptyString(ba
     /// running) will be sent along to the server. The default is false.
     /// </summary>
     public bool UseDefaultCredentials { get; set; }
+    
+    /// <summary>
+    /// Set to true if you need the Content-Type not to have the charset 
+    /// </summary>
+    public bool DisableCharset { get; set; }
 
 #if NETSTANDARD
     public DecompressionMethods AutomaticDecompression { get; set; } = DecompressionMethods.GZip;

test/RestSharp.IntegrationTests/RequestBodyTests.cs

@@ -9,16 +9,18 @@ public class RequestBodyTests : IClassFixture<RequestBodyFixture> {
 
     const string NewLine = "\r\n";
 
-    const string TextPlainContentType    = "text/plain";
-    const string ExpectedTextContentType = $"{TextPlainContentType}; charset=utf-8";
+    const string TextPlainContentType             = "text/plain";
+    const string ExpectedTextContentType          = $"{TextPlainContentType}; charset=utf-8";
+    const string ExpectedTextContentTypeNoCharset = TextPlainContentType;
 
     public RequestBodyTests(RequestBodyFixture fixture, ITestOutputHelper output) {
         _output = output;
         _server = fixture.Server;
     }
 
-    async Task AssertBody(Method method) {
-        var client = new RestClient(_server.Url);
+    async Task AssertBody(Method method, bool disableCharset = false) {
+        var options = new RestClientOptions(_server.Url) { DisableCharset = disableCharset };
+        var client  = new RestClient(options);
 
         var request = new RestRequest(RequestBodyCapturer.Resource, method) {
             OnBeforeRequest = async m => {
@@ -33,7 +35,8 @@ async Task AssertBody(Method method) {
 
         await client.ExecuteAsync(request);
 
-        AssertHasRequestBody(ExpectedTextContentType, bodyData);
+        var expected = disableCharset ? ExpectedTextContentTypeNoCharset : ExpectedTextContentType;
+        AssertHasRequestBody(expected, bodyData);
     }
 
     [Fact]
@@ -48,9 +51,15 @@ async Task AssertBody(Method method) {
     [Fact]
     public Task Can_Be_Added_To_PATCH_Request() => AssertBody(Method.Patch);
 
+    [Fact]
+    public Task Can_Be_Added_To_POST_Request_NoCharset() => AssertBody(Method.Post, true);
+    
     [Fact]
     public Task Can_Be_Added_To_POST_Request() => AssertBody(Method.Post);
 
+    [Fact]
+    public Task Can_Be_Added_To_PUT_Request_NoCharset() => AssertBody(Method.Put, true);
+
     [Fact]
     public Task Can_Be_Added_To_PUT_Request() => AssertBody(Method.Put);
 
@@ -108,7 +117,7 @@ public async Task Query_Parameters_With_Json_Body() {
             .AddQueryParameter("key", "value");
 
         await client.ExecuteAsync(request);
-        
+
         RequestBodyCapturer.CapturedUrl.ToString().Should().Be($"{_server.Url}Capture?key=value");
         RequestBodyCapturer.CapturedContentType.Should().Be("application/json; charset=utf-8");
         RequestBodyCapturer.CapturedEntityBody.Should().Be("{\"displayName\":\"Display Name\"}");