Small docs update and multipart form content type format override

Author: alexeyzimarev

docs/usage.md

@@ -298,33 +298,33 @@ public async Task<RestResponse> ExecuteAsync(
 You can also avoid setting the request method upfront and use one of the overloads:
 
 ```csharp
-Task<RestResponse> ExecuteGetAsync
-Task<RestResponse> ExecutePostAsync
-Task<RestResponse> ExecutePutAsync
+Task<RestResponse> ExecuteGetAsync(RestRequest request, CancellationToken cancellationToken)
+Task<RestResponse> ExecutePostAsync(RestRequest request, CancellationToken cancellationToken)
+Task<RestResponse> ExecutePutAsync(RestRequest request, CancellationToken cancellationToken)
 ```
 
 When using any of those methods, you will get the response content as string in `response.Content`.
 
 RestSharp can deserialize the response for you. To use that feature, use one of the generic overloads:
 
 ```csharp
-Task<RestResponse<T>> ExecuteAsync<T>
-Task<RestResponse<T>> ExecuteGetAsync<T>
-Task<RestResponse<T>> ExecutePostAsync<T>
-Task<RestResponse<T>> ExecutePutAsync<T>
+Task<RestResponse<T>> ExecuteAsync<T>(RestRequest request, CancellationToken cancellationToken)
+Task<RestResponse<T>> ExecuteGetAsync<T>(RestRequest request, CancellationToken cancellationToken)
+Task<RestResponse<T>> ExecutePostAsync<T>(RestRequest request, CancellationToken cancellationToken)
+Task<RestResponse<T>> ExecutePutAsync<T>(RestRequest request, CancellationToken cancellationToken)
 ```
 
 All the overloads that return `RestResponse` or `RestResponse<T>` don't throw an exception if the server returns an error. Read more about it [here](error-handling.md).
 
 If you just need a deserialized response, you can use one of the extensions:
 
 ```csharp
-Task<T> GetAsync<T>
-Task<T> PostAsync<T>
-Task<T> PutAsync<T>
-Task<T> HeadAsync<T>
-Task<T> PatchAsync<T>
-Task<T> DeleteAsync<T>
+Task<T> GetAsync<T>(RestRequest request, CancellationToken cancellationToken)
+Task<T> PostAsync<T>(RestRequest request, CancellationToken cancellationToken)
+Task<T> PutAsync<T>(RestRequest request, CancellationToken cancellationToken)
+Task<T> HeadAsync<T>(RestRequest request, CancellationToken cancellationToken)
+Task<T> PatchAsync<T>(RestRequest request, CancellationToken cancellationToken)
+Task<T> DeleteAsync<T>(RestRequest request, CancellationToken cancellationToken)
 ```
 
 Those extensions will throw an exception if the server returns an error, as there's no other way to float the error back to the caller.

package.json

@@ -1,6 +1,6 @@
 {
   "devDependencies": {
-    "vuepress-vite": "2.0.0-beta.27"
+    "vuepress-vite": "^2.0.0-beta.33"
   },
   "scripts": {
     "docs:dev": "vuepress dev docs",

src/RestSharp/Request/HttpContentExtensions.cs

@@ -22,9 +22,9 @@ public static class HttpContentExtensions {
 
     public static string GetFormBoundary(this MultipartFormDataContent content) {
         return GetBoundary(content);
-        var contentType = content.Headers.ContentType?.ToString();
-        var index       = contentType?.IndexOf("boundary=", StringComparison.Ordinal) ?? 0;
-        return index > 0 ? GetFormBoundary(contentType!, index) : "";
+        // var contentType = content.Headers.ContentType?.ToString();
+        // var index       = contentType?.IndexOf("boundary=", StringComparison.Ordinal) ?? 0;
+        // return index > 0 ? GetFormBoundary(contentType!, index) : "";
     }
 
     static string GetFormBoundary(string headerValue, int index) {

src/RestSharp/Request/RequestContent.cs

@@ -187,7 +187,7 @@ void AddHeader(Parameter parameter) {
 
     string GetContentTypeHeader(string contentType)
         => Content is MultipartFormDataContent mpContent
-            ? $"{contentType}; boundary=\"{mpContent.GetFormBoundary()}\""
+            ? _request.FormatMultipartContentType(contentType, mpContent.GetFormBoundary())
             : contentType;
 
     public void Dispose() {

src/RestSharp/Request/RestRequest.cs

@@ -17,6 +17,8 @@
 
 namespace RestSharp;
 
+public delegate string FormatContentTypeHeader(string contentType, string formBoundary);
+
 /// <summary>
 /// Container for data used to make requests
 /// </summary>
@@ -145,6 +147,11 @@ public RestRequest(Uri resource, Method method = Method.Get)
     /// </summary>
     public HttpCompletionOption CompletionOption { get; set; } = HttpCompletionOption.ResponseContentRead;
 
+    /// <summary>
+    /// Function that formats the content type header for multipart form fata
+    /// </summary>
+    public FormatContentTypeHeader FormatMultipartContentType { get; set; } = (contentType, boundary) => $"{contentType}; boundary=\"{boundary}\"";
+
     /// <summary>
     /// Set this to write response to Stream rather than reading into memory.
     /// </summary>