docs: function(opts) {
    opts = opts || {};
    this.userHandshake = opts.handshake;
  
    if(opts.heartbeat) {
      this.heartbeatSec = opts.heartbeat;
      this.heartbeat = opts.heartbeat * 1000;
    }
  
    this.checkClient = opts.checkClient;
  
    this.useDict = opts.useDict;
    this.useProtobuf = opts.useProtobuf;
    this.useCrypto = opts.useCrypto;
  }