[librdkafka] RD_KAFKA_BROKER_STATE_DOWN

Hello! I’m having some problems with librdkafka.

Why does rd_kafka_produce() always seem to succeed, even if there is a problem connecting to the Kafka brokers?
What caused the produce client frequently disconnected from the broker during use? Configuration? Network? or Other reasons?
Following info by tracking the logs in the kafka_broker.c by myself:

61742 [ERROR] [2022-09-07 10:33:03] [rdkafka_broker.c]-Ln5057 rkb_state:RD_KAFKA_BROKER_STATE_DOWN,TRY_CONNECT again
61743 [ERROR] [2022-09-07 10:33:03] [rdkafka_broker.c]-Ln3328 A connection to this broker is needed,abs_timeout:0
61744 [ERROR] [2022-09-07 10:33:03] [rdkafka_broker.c]-Ln5057 rkb_state:RD_KAFKA_BROKER_STATE_DOWN,TRY_CONNECT again
61745 [ERROR] [2022-09-07 10:33:03] [rdkafka_broker.c]-Ln3328 A connection to this broker is needed,abs_timeout:0
61746 [ERROR] [2022-09-07 10:33:03] [rdkafka_broker.c]-Ln5057 rkb_state:RD_KAFKA_BROKER_STATE_DOWN,TRY_CONNECT again
61747 [ERROR] [2022-09-07 10:33:03] [rdkafka_broker.c]-Ln3328 A connection to this broker is needed,abs_timeout:0
61748 [ERROR] [2022-09-07 10:33:03] [rdkafka_broker.c]-Ln5057 rkb_state:RD_KAFKA_BROKER_STATE_DOWN,TRY_CONNECT again
61749 [ERROR] [2022-09-07 10:33:03] [rdkafka_broker.c]-Ln3328 A connection to this broker is needed,abs_timeout:0
61750 [ERROR] [2022-09-07 10:33:03] [rdkafka_broker.c]-Ln5057 rkb_state:RD_KAFKA_BROKER_STATE_DOWN,TRY_CONNECT again
61751 [ERROR] [2022-09-07 10:33:03] [rdkafka_broker.c]-Ln3328 A connection to this broker is needed,abs_timeout:0
61752 [ERROR] [2022-09-07 10:33:03] [rdkafka_broker.c]-Ln5057 rkb_state:RD_KAFKA_BROKER_STATE_DOWN,TRY_CONNECT again
61753 [ERROR] [2022-09-07 10:33:03] [rdkafka_broker.c]-Ln3328 A connection to this broker is needed,abs_timeout:0
61754 [ERROR] [2022-09-07 10:33:03] [rdkafka_broker.c]-Ln5057 rkb_state:RD_KAFKA_BROKER_STATE_DOWN,TRY_CONNECT again
61755 [ERROR] [2022-09-07 10:33:03] [rdkafka_broker.c]-Ln3328 A connection to this broker is needed,abs_timeout:0

another quertion is that whether the numbers of TCP links between the produce and the brokers can be controlled by configuration without changing the configuration of the server?

Any help is apreciated! Thanks in advance.