private static void setAttributeCombinerTransform(ImmutableSDField field, SummaryField summaryField) {
        if (summaryField.hasUnresolvedType()) {
            summaryField.setResolvedDataType(field.getDataType());
        }
        if (summaryField.getTransform() == SummaryTransform.NONE) {
            summaryField.setTransform(SummaryTransform.ATTRIBUTECOMBINER);
        }
    }
Adds the data type and attribute summary transform ({@link SummaryTransform#ATTRIBUTE} to all {@link SummaryField} having an imported
field as source.

@author bjorncs
config-model/src/main/java/com/yahoo/schema/processing/AddDataTypeAndTransformToSummaryOfImportedFields.java