Add destroy data_chunk

appender.go

@@ -67,15 +67,18 @@ func (a *Appender) Error() error {
 
 // Flush the appender to the underlying table and clear the internal cache.
 func (a *Appender) Flush() error {
+	// set the size of the current chunk to the current row
 	C.duckdb_data_chunk_set_size(a.chunks[a.currentChunkIdx], C.uint64_t(a.currentRow))
 
+	// append all chunks to the appender and destroy them
 	var rv C.duckdb_state
 	for i, chunk := range a.chunks {
 		rv = C.duckdb_append_data_chunk(*a.appender, chunk)
 		if rv == C.DuckDBError {
 			dbErr := C.GoString(C.duckdb_appender_error(*a.appender))
 			return fmt.Errorf("duckdb error appending chunk %d of %d: %s", i+1, a.currentChunkIdx+1, dbErr)
 		}
+		C.duckdb_destroy_data_chunk(&chunk)
 	}
 
 	if state := C.duckdb_appender_flush(*a.appender); state == C.DuckDBError {