Identity broker logout request send to external identity provider don't contain id_token_hint

Keycloak is used as Identity broker and external IDP is configured and had successfully sign in external IDP and get keycloak access token. I had problem in logout when call logout keycloak logout uri it redirect to IDP logout uri but without id_token_hint parameter which is required for logout request. how to force keycloak to send id_token_hint parameter in logout uri ?

keycloak logout response:
location: https://{exterrnal-idp-url}/oauth/v2/session/logout?state=2bb3df57-781d-42e6-90f0-c52d70a57056&post_logout_redirect_uri=https%3A%2F%2F{keycloak-url}%2Frealms%2F{realm}%2Fbroker%2Foidc%2Fendpoint%2Flogout_response