public B contactPoints(String contactPoints) {
    if (contactPoints == null) throw new NullPointerException("contactPoints == null");
    this.contactPoints = contactPoints;
    return (B) this;
  }
Comma separated list of host addresses part of Cassandra cluster. You can also specify a custom
port with 'host:port'. Defaults to localhost on port 9042 *
zipkin-storage/cassandra/src/main/java/zipkin2/storage/cassandra/CassandraStorageBuilder.java