Client is closed without any error or explicit disconnection

[j-a-m-l]

The client does not keep the connection open.

This is the log:

D, [2020-02-25T13:17:27.841007 #8033] DEBUG -- WebSocket: Opening Connection to echo.websocket.org on port 443
D, [2020-02-25T13:17:28.152761 #8033] DEBUG -- WebSocket: Upgrading Connection #<TCPSocket:0x0000563f0fe42920> to ssl
I, [2020-02-25T13:17:28.485178 #8033]  INFO -- WebSocket: Connection #<TCPSocket:0x0000563f0fe42920> upgraded to #<OpenSSL::SSL::SSLSocket:0x0000563f0fe41e30>
D, [2020-02-25T13:17:28.493191 #8033] DEBUG -- WebSocket: Initiating handshake on #<OpenSSL::SSL::SSLSocket:0x0000563f0fe41e30>
D, [2020-02-25T13:17:28.493381 #8033] DEBUG -- WebSocket: Starting reactor
I, [2020-02-25T13:17:28.493497 #8033]  INFO -- WebSocket: Client #<OpenSSL::SSL::SSLSocket:0x0000563f0fe41e30> connected to wss://echo.websocket.org

This is the code that I'm using:

NIO::WebSocket.logger.level = Logger::DEBUG

url = 'wss://echo.websocket.org'

NIO::WebSocket.connect url do |driver|
  driver.on :open do |_event|
    puts 'OPEN'
  end
  driver.on :close do |_event|
    puts 'CLOSE'
  end
  driver.on :error do |_event|
    puts 'ERROR'
  end
  driver.on :io_error do |_event|
    puts 'IO ERROR'
  end
  driver.on :message do |event|
    puts event.data
  end
end