下面在调用币安的接口时，经常会卡住，设置连接超时也不会抛出异常，代码如下（默认连接超时为nil, 参考：https://github.com/ruby/ruby/pull/269）：

require 'net/http'
require 'json'
require 'byebug'

uri = URI('https://www.binance.com/api/v1/ticker/24hr?symbol=EOSBTC')

req = Net::HTTP::Get.new(uri)

loop do
  res = Net::HTTP.start(uri.hostname, uri.port, :use_ssl => uri.scheme == 'https') do |http|
    http.open_timeout = 1
    http.request(req)
  end

  puts "#{JSON.parse res.body}"
  puts "http request complete."
  sleep 1
end

不知道为什么，用 http.open_timeout = 1 这种设置不奏效，改为在start的options中配置即可则会超时抛出异常，如下：

  res = Net::HTTP.start(uri.hostname, uri.port, :use_ssl => uri.scheme == 'https', :open_timeout => 1) do |http|
    http.request(req)
  end