RequestBodyBuilder (http-support 18.1.0 API)

```
public interface RequestBodyBuilder
```
A builder interface for defining the body of a request.

This interface provides several methods for defining a request body with different content. It is used for both regular request bodies and the bodies of the parts of a multipart request. An implementation is passed to a consumer which then invokes the desired method to set the body. Note that the methods are mutually exclusive; a concrete builder instance will allow only a single method call.

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`void`	`file(Path path, String mediaType)`	Sets the request body as a file.
`void`	`json(Object payload)`	Sets the request body as an object that is serialized to JSON.
`void`	`string(String body, String mediaType)`	Sets the request body as a string.

- Method Detail
  - string
```
void string(String body,
            String mediaType)
```
    Sets the request body as a string. Based on the media type, the content header is set.
    
    Parameters:
    
    body - the request body as string
    
    mediaType - the media type of the content
  - file
```
void file(Path path,
          String mediaType)
```
    Sets the request body as a file. This can be used to upload files to a server. Based on the media type, the content header is set.
    
    Parameters:
    
    path - the path to the file to be uploaded
    
    mediaType - the media type of the content
  - json
```
void json(Object payload)
```
    Sets the request body as an object that is serialized to JSON. This method uses an internal JSON object mapper to generate a JSON representation from the object passed in. It also automatically sets a correct Content-Type header.
    
    Parameters:
    
    payload - the object to be used as request payload