code: public static ByteBuffer fromUtf8String(CharSequence utfString) {
          if (utfString == null || utfString.length() == 0) {
              return Buffers.EMPTY_BYTE_BUFFER;
          } else {
              return ByteBuffer.wrap(utfString.toString().getBytes(StandardCharsets.UTF_8));
          }
      }
docs: Create a {@link ByteBuffer} which holds the UTF8 encoded bytes for the
  given {@link String}.
  
  @param utfString The {@link String} to convert
  @return buffer   The {@link ByteBuffer} which was created