# File lib/net/http.rb, line 1137
    def initialize_http_header(initheader)
      @header = {}
      return unless initheader
      initheader.each do |key, value|
        warn "net/http: warning: duplicated HTTP header: #{key}" if key?(key) and $VERBOSE
        @header[key.downcase] = [value.strip]
      end
    end