Fix missing messages return on finish() call

Author: mac-cain13

Readme.md

@@ -55,7 +55,9 @@ Task {
             }
         }
     } catch {
-        try await parser.finish()
+        // Calling finish might return messages that are considered complete now we know no more data is comming in. (For example a single HTTP request with no content length set.)
+        // It can also fail if the HTTP message is invalid at this point and throw an error. 
+        let messages = try? await parser.finish()
     }
 }
 ```

Sources/llhttp/HTTPMessagesParser.swift

@@ -207,9 +207,12 @@ public actor HTTPMessagesParser<MessageType: HTTPMessageType> {
         ///
         /// Requests without Content-Length and other messages might require treating all incoming bytes as the part of the body, up to the last byte of the connection.
         ///
-        /// This method will trigger the callback if the request was terminated safely. Otherwise a error code would be returned.
-        public func finish() async throws {
+        /// This method will trigger the callback if the request was terminated safely. Otherwise an error would be thrown.
+        public func finish() async throws -> [MessageType] {
             try llhttp.finish()
+
+            defer { messagesCollector = [] }
+            return messagesCollector
         }
     }
 }