@Bean SessionFactory sessionFactory() {
    return SessionFactory.DEFAULT;
  }
This storage accepts Cassandra logs in a specified category. Each log entry is expected to
contain a single span, which is TBinaryProtocol big-endian, then base64 encoded. Decoded spans
are stored asynchronously.
zipkin-server/src/main/java/zipkin2/server/internal/cassandra3/ZipkinCassandra3StorageConfiguration.java