Replace assert with debug_assert for ArrowArrayStream pointer validation

Author: kosiew

src/dataframe.rs

@@ -970,9 +970,9 @@ impl PyDataFrame {
 
         let stream = Box::new(FFI_ArrowArrayStream::new(reader));
         let stream_ptr = Box::into_raw(stream);
-        assert!(
+        debug_assert!(
             !stream_ptr.is_null(),
-            "ArrowArrayStream pointer should never be null"
+            "ArrowArrayStream pointer should never be null",
         );
         let capsule = unsafe {
             ffi::PyCapsule_New(