protected void checkSealed() {
        if (sealed) {
            throw new IllegalStateException("Sealed request is immutable");
        }
    }
Loads data from deferred input stream. This will remove custom writer set by
{@link #data(ClickHouseWriter)}.

@param input input stream
@return mutation request
clickhouse-client/src/main/java/com/clickhouse/client/ClickHouseRequest.java