public B ensureSchema(boolean ensureSchema) {
    if (ensureSchema) {
      this.ensureSchema = Schema::ensure;
    } else {
      this.ensureSchema = Schema::validate;
    }
    return (B) this;
  }
Override to control how sessions are created.
zipkin-storage/cassandra/src/main/java/zipkin2/storage/cassandra/CassandraStorageBuilder.java