diff --git a/Sources/AWSLambdaRuntime/Lambda+LocalServer.swift b/Sources/AWSLambdaRuntime/Lambda+LocalServer.swift
index baa08a44..56786697 100644
--- a/Sources/AWSLambdaRuntime/Lambda+LocalServer.swift
+++ b/Sources/AWSLambdaRuntime/Lambda+LocalServer.swift
@@ -238,7 +238,7 @@ private struct LambdaHTTPServer {
                         requestHead = head
 
                     case .body(let body):
-                        requestBody = body
+                        requestBody.setOrWriteImmutableBuffer(body)
 
                     case .end:
                         precondition(requestHead != nil, "Received .end without .head")