fix: tracing fastapi app

Signed-off-by: minatooni <minato.work.i.mm@gmail.com>

Author: minatooni

src/instana/instrumentation/fastapi.py

@@ -71,6 +71,10 @@ def init_with_instana(
             kwargs["middleware"] = [Middleware(InstanaASGIMiddleware)]
         elif isinstance(middleware, list):
             middleware.append(Middleware(InstanaASGIMiddleware))
+        elif isinstance(middleware, tuple):
+            kwargs["middleware"] =  (*middleware, Middleware(InstanaASGIMiddleware))
+        else:
+            logger.warning("Trace cannot be sent to Instana: unsupported middleware sequence type.")
 
         exception_handlers = kwargs.get("exception_handlers")
         if exception_handlers is None: