value: String,
    ) = apply {
      headersCheckName(name)
      addLenient(name, value)
    }

    /**
     * Adds all headers from an existing collection.
     */
    fun addAll(headers: Headers) = commonAddAll(headers)

    /**
     * Add a header with the specified name and formatted date. Does validation of header names and
     * value.
     */
    fun add(
      name: String,