public Builder format(String format) {
            if (!ClickHouseChecker.isNullOrBlank(format)) {
                this.format = ClickHouseFormat.valueOf(format);
            }
            return this;
        }
Sets deferred content.

@param content non-null deferred content
@return this builder
clickhouse-data/src/main/java/com/clickhouse/data/ClickHouseExternalTable.java