default List<AggregatedBodyPart> fields(String name) {
        requireNonNull(name, "name");
        return bodyParts().stream()
                          .filter(part -> name.equals(part.name()))
                          .collect(toImmutableList());
    }
Returns the body parts identified by the given control name. The control
name is the {@code name} parameter of the {@code "content-disposition"}
header for a body part with disposition type {@code form-data}.

@param name control name
core/src/main/java/com/linecorp/armeria/common/multipart/AggregatedMultipart.java