docs: public final String getFullString(final int pos, final int len, String charsetName) {
          if (pos + len > limit || pos < 0) throw new IllegalArgumentException("limit excceed: "
                                                                               + (pos < 0 ? pos : (pos + len)));
  
          try {
              return new String(buffer, origin + pos, len, charsetName);
          } catch (UnsupportedEncodingException e) {
              throw new IllegalArgumentException("Unsupported encoding: " + charsetName, e);
          }
      }