Defines the provider of events and data of a topic.
BOOL(* Provider::Publish) ([IUnknown]($api-api-LinkIoT-IUnknown.md) *iUnknown, const [Topic]($api-api-LinkIoT-Broadcast.md#gaf03f5bc94cad32ab628a6cdee09b0542) *topic, uint8 *data, int16 len)
Publishes events and data of a specified topic.
The events or data is published by the publisher, sent to all consumers who have subscribed to the topic, and processed by the consumers.
Returns TRUE if the topic is successfully published; returns FALSE otherwise.