Add optional body to delete (#439)

The spec discourages but does not forbid a body. Allow a body argument
without falling back on the `send` API since some servers may be
designed specifically to require it.

Closes #383, closes #206

Author: Julian

CHANGELOG.md

@@ -11,6 +11,8 @@ null safety allow list.
 
 * Add `const` constructor to `ByteStream`.
 * Migrate `BrowserClient` from `blob` to `arraybuffer`.
+* **Breaking** Added a `body` and `encoding` argument to `Client.delete`. This
+  is only breaking for implementations which override that method.
 
 ## 0.12.2
 

lib/http.dart

@@ -127,8 +127,10 @@ Future<Response> patch(Object url,
 /// the same server, you should use a single [Client] for all of those requests.
 ///
 /// For more fine-grained control over the request, use [Request] instead.
-Future<Response> delete(Object url, {Map<String, String>? headers}) =>
-    _withClient((client) => client.delete(url, headers: headers));
+Future<Response> delete(Object url,
+        {Map<String, String>? headers, Object? body, Encoding? encoding}) =>
+    _withClient((client) =>
+        client.delete(url, headers: headers, body: body, encoding: encoding));
 
 /// Sends an HTTP GET request with the given headers to the given URL, which can
 /// be a [Uri] or a [String], and returns a Future that completes to the body of

lib/src/base_client.dart

@@ -42,8 +42,9 @@ abstract class BaseClient implements Client {
       _sendUnstreamed('PATCH', url, headers, body, encoding);
 
   @override
-  Future<Response> delete(Object url, {Map<String, String>? headers}) =>
-      _sendUnstreamed('DELETE', url, headers);
+  Future<Response> delete(Object url,
+          {Map<String, String>? headers, Object? body, Encoding? encoding}) =>
+      _sendUnstreamed('DELETE', url, headers, body, encoding);
 
   @override
   Future<String> read(Object url, {Map<String, String>? headers}) async {

lib/src/client.dart

@@ -110,7 +110,8 @@ abstract class Client {
   /// which can be a [Uri] or a [String].
   ///
   /// For more fine-grained control over the request, use [send] instead.
-  Future<Response> delete(Object url, {Map<String, String>? headers});
+  Future<Response> delete(Object url,
+      {Map<String, String>? headers, Object? body, Encoding? encoding});
 
   /// Sends an HTTP GET request with the given headers to the given URL, which
   /// can be a [Uri] or a [String], and returns a Future that completes to the