Creates a new topic handle for topic named \p topic_str
\p conf is an optional configuration for the topic that will be used
instead of the default topic configuration.
The \p conf object is reusable after this call.
the new topic handle or null on error (see \p errstr).
Creates a new topic handle for topic named \p topic_str
\p conf is an optional configuration for the topic that will be used instead of the default topic configuration. The \p conf object is reusable after this call.
the new topic handle or null on error (see \p errstr).