code: @Deprecated
      @Override
      protected int write(int offset, int length) {
          int newLength=charsLength+length;
          ensureCapacity(newLength);
          charsLength=newLength;
          int charsOffset=chars.length-charsLength;
          while(length>0) {
              chars[charsOffset++]=strings.charAt(offset++);
              --length;
          }
          return charsLength;
      }
docs: {@inheritDoc}
  @deprecated This API is ICU internal only.
  @hide draft / provisional / internal are hidden on Android