code: public OkRequest<T> send(final CharSequence value) {
  
          openOutput();
          try {
              mOutput.write(value.toString());
          } catch (IOException e) {
              deliverError(new ParseError(e));
          }
  
          return this;
      }
docs: Write char sequence to request body
  <p/>
  The charset configured via {@link #contentType(String)} will be used and
  UTF-8 will be used if it is unset.
  
  @param value
  @return this request