diff --git a/Source/SocketIO/Engine/SocketEngineSpec.swift b/Source/SocketIO/Engine/SocketEngineSpec.swift
index 89f068f..0f549db 100644
--- a/Source/SocketIO/Engine/SocketEngineSpec.swift
+++ b/Source/SocketIO/Engine/SocketEngineSpec.swift
@@ -161,12 +161,7 @@ extension SocketEngineSpec {
 
     func createBinaryDataForSend(using data: Data) -> Either<Data, String> {
         if websocket {
-            var byteArray = [UInt8](repeating: 0x4, count: 1)
-            let mutData = NSMutableData(bytes: &byteArray, length: 1)
-
-            mutData.append(data)
-
-            return .left(mutData as Data)
+            return .left(Data(bytes: [0x4]) + data)
         } else {
             return .right("b4" + data.base64EncodedString(options: Data.Base64EncodingOptions(rawValue: 0)))
         }