diff --git a/vortex-ffi/src/lib.rs b/vortex-ffi/src/lib.rs
--- a/vortex-ffi/src/lib.rs
+++ b/vortex-ffi/src/lib.rs
@@ -8,4 +8,5 @@
 mod array;
+mod callback_io;
 mod array_iterator;
 mod binary;
 mod data_source;