code: public Map<String, Object> build() {
          final ImmutableMap.Builder<String, Object> builder = ImmutableMap.builder();
          ofNullable(remotePath).map(x -> builder.put("remotePath", x));
          ofNullable(user).map(x -> builder.put("user", x));
          ofNullable(pass).map(x -> builder.put("pass", x));
          ofNullable(method).map(x -> builder.put("method", x));
          return builder.build();
      }
docs: Builds a map, which is ready to be passed to the subordinated
  Appium API.
  
  @return arguments mapping.