@SuppressWarnings("unchecked")
    public T field(String fieldName, FormatInfo fieldFormatInfo) {
        checkNotNull(fieldName);
        checkNotNull(fieldFormatInfo);
        checkNotDuplicated(fieldName);

        fieldNames.add(fieldName);
        fieldFormatInfos.add(fieldFormatInfo);

        return (T) this;
    }
Defines the format for the next field.

@param fieldName The name of the field.
@param fieldFormatInfo The format of the field.
inlong-sort/sort-formats/format-common/src/main/java/org/apache/inlong/sort/formats/base/TextFormatDescriptor.java