static Multipart of(String boundary, Iterable<? extends BodyPart> parts) {
        requireNonNull(boundary, "boundary");
        requireNonNull(parts, "parts");
        final BodyPart[] bodyParts = Iterables.toArray(parts, BodyPart.class);
        return new DefaultMultipart(boundary, StreamMessage.of(bodyParts));
    }
Returns a new {@link Multipart} with the specified {@code boundary} and {@link BodyPart}s.
core/src/main/java/com/linecorp/armeria/common/multipart/Multipart.java