presto-main/src/main/java/io/prestosql/sql/gen/JoinCompiler.java/JoinCompiler/generateGetSizeInBytesMethod
class JoinCompiler:    private static void generateGetSizeInBytesMethod(ClassDefinition classDefinition, FieldDefinition sizeField)
    {
        MethodDefinition getSizeInBytesMethod = classDefinition.declareMethod(a(PUBLIC), "getSizeInBytes", type(long.class));

        Variable thisVariable = getSizeInBytesMethod.getThis();
        getSizeInBytesMethod.getBody()
                .append(thisVariable.getField(sizeField))
                .retLong();
    }