code: @Override
      public StrBuilder append(final char ch) {
          final int len = length();
          ensureCapacity(len + 1);
          buffer[size++] = ch;
          return this;
      }
docs: Appends a char value to the string builder.
  
  @param ch  the value to append
  @return this, to enable chaining
  @since 3.0