in src/main/java/org/apache/cassandra/distributed/api/QueryResults.java [102:112]
public Builder row(Object... values)
{
if (numColumns == UNSET)
numColumns = values.length;
if (numColumns != values.length)
throw new AssertionError("Attempted to add row with different column count; " +
"expected " + numColumns + " columns but given " + Arrays.toString(values));
results.add(values);
return this;
}