void addField(final String name, final String value) {
        addField(new MimeField(name, value));
    }
MultipartPart class represents a content body that can be used as a part of multipart encoded
entities. This class automatically populates the header with standard fields based on
the content description of the enclosed body.

@since 5.0
httpclient5/src/main/java/org/apache/hc/client5/http/entity/mime/MultipartPart.java