Add synchronize function (#1006)

* add synchronize function

* fix linux

* fix linux

* fix and fix docs

* fix test

* try synchronize in stream destroy

* synchronize works for both cpu and gpu

python/src/stream.cpp

@@ -129,4 +129,17 @@ void init_stream(nb::module_& m) {
               # Operations here will use mx.cpu by default.
               pass
       )pbdoc");
+  m.def(
+      "synchronize",
+      [](const std::optional<Stream>& s) {
+        s ? synchronize(s.value()) : synchronize();
+      },
+      "stream"_a = nb::none(),
+      R"pbdoc(
+      Synchronize with the given stream.
+
+      Args:
+        (Stream, optional): The stream to synchronize with. If ``None`` then
+           the default stream of the default device is used. Default: ``None``.
+      )pbdoc");
 }