): Builder {
      var pos = input.indexOfFirstNonAsciiWhitespace()
      val limit = input.indexOfLastNonAsciiWhitespace(pos)

      // Scheme.
      val schemeDelimiterOffset = schemeDelimiterOffset(input, pos, limit)
      if (schemeDelimiterOffset != -1) {
        when {
          input.startsWith("https:", ignoreCase = true, startIndex = pos) -> {
            this.scheme = "https"
            pos += "https:".length