JavaDSL Missing Documentation / Verboseness

via @schmitch

----

missing documentation makes some things really really hard to figure out (javadoc/scaladoc is not enough).
I guess Multiparts is probably a well known example of that since for a simple 1 file + FormData you need to:

```
Map dataMap = new HashMap<>();
dataMap.put("hello", "world");
RequestEntity entity = FormData.create(dataMap).toEntity();
Multipart.FormData.BodyPart bp1 = Multiparts.createFormDataBodyPartStrict("hase", (HttpEntity.Strict)entity);
Multipart.FormData.BodyPart bp2 = Multiparts.createFormDataPartFromPath("blabla", ContentTypes.APPLICATION_OCTET_STREAM, new File("").toPath());

Multipart.FormData mpf = Multiparts.createFormDataFromParts(bp1, bp2);
mpf.toEntity("boundary");
```

Maybe there is a simplier way, but I couldn't find one? (Btw. the server side looks extremly verbose as well).

The issue does not name any files, tests, or entry points. Start by locating the Java DSL multipart APIs referenced in the example, then determine which usage guidance is missing; done means documenting a simpler multipart example and clarifying the related server-side verbosity.

Written by the indexing model from the issue text.