diff --git a/arrow-ipc/src/writer.rs b/arrow-ipc/src/writer.rs
index 4b0f4a00b51..09e9da8c92e 100644
--- a/arrow-ipc/src/writer.rs
+++ b/arrow-ipc/src/writer.rs
@@ -892,8 +892,10 @@ impl<W: Write> FileWriter<W> {
         // write the schema
         let encoded_message = data_gen.schema_to_bytes(schema, &write_options);
 
-        let (meta, _data) =
+        let (meta, data) =
             write_message(&mut writer, written_len, encoded_message, &write_options)?;
+        // The schema message has no body
+        debug_assert_eq!(data, 0);
 
         // written bytes = padded_magic + schema
         written_len += meta;