serialize all secrets.
This flag is ignored if any of NM_CONNECTION_SERIALIZE_WITH_SECRETS_AGENT_OWNED, NM_CONNECTION_SERIALIZE_WITH_SECRETS_SYSTEM_OWNED or NM_CONNECTION_SERIALIZE_WITH_SECRETS_NOT_SAVED is set. Since 1.32.
NM_CONNECTION_SERIALIZE_WITH_SECRETS_AGENT_OWNED
NM_CONNECTION_SERIALIZE_WITH_SECRETS_SYSTEM_OWNED
NM_CONNECTION_SERIALIZE_WITH_SECRETS_NOT_SAVED