docs: private static Writer unwrap(Writer out) throws IOException {
  		while(true) {
  			Class<? extends Writer> outClass = out.getClass();
  			// Note: bodyContentImplClass will be null when direct access disabled
  			if(outClass==bodyContentImplClass) {
  				try {
  					Writer writer = (Writer)writerField.get(out);
  					// When the writer field is non-null, BodyContent is pass-through and we may safely directly access the wrapped writer.
  					if(writer!=null) {
  						// Will keep looping to unwrap the wrapped out
  						out = writer;
  					} else {
  						// BodyContent is buffering, must use directly
  						return out;
  					}
  				} catch(IllegalAccessException e) {
  					throw new IOException(e);
  				}
  			} else {
  				// No unwrapping
  				return out;
  			}
  		}
  	}