Enhance drop_stream function to retrieve and free original stream pointer for improved memory management

Author: kosiew

src/dataframe.rs

@@ -66,6 +66,7 @@ unsafe extern "C" fn drop_stream(capsule: *mut ffi::PyObject) {
         return;
     }
     let name = ARROW_STREAM_NAME.get_or_init(|| CString::new("arrow_array_stream").unwrap());
+    // Retrieve the original stream pointer and free it when the capsule drops
     let stream_ptr = ffi::PyCapsule_GetPointer(capsule, name.as_ptr()) as *mut FFI_ArrowArrayStream;
     if !stream_ptr.is_null() {
         drop(Box::from_raw(stream_ptr));