code: public static void insert (final CharSequence aSeq, final int nIndex, @Nonnull final Codepoint aCodepoint)
    {
      insert (aSeq, nIndex, aCodepoint.getValue ());
    }
docs: Insert a codepoint into the buffer, automatically dealing with surrogate
  pairs
  
  @param aSeq
  source sequence
  @param nIndex
  index
  @param aCodepoint
  codepoint to be inserted