fix example

Author: mabdinur

examples/ffi/trace_exporter.c

@@ -100,8 +100,8 @@ int main(int argc, char** argv)
         .interval = 60000,
         .runtime_id = DDOG_CHARSLICE_C("12345678-1234-1234-1234-123456789abc"),
         .debug_enabled = true,
-        .session_id = DDOG_CHARSLICE_C(""),
-        .root_session_id = DDOG_CHARSLICE_C(""),
+        .session_id = DDOG_CHARSLICE_C("12345678-1234-1234-1234-123456789abc"),
+        .root_session_id =DDOG_CHARSLICE_C("87654321-1234-1234-1234-123456789abc"),
         .parent_session_id = DDOG_CHARSLICE_C(""),
     };