1. 在客户端配置中添加自定义重连策略：

connection.onreconnecting(() => {
    console.log('Connection lost, reconnecting...');
});

connection.onreconnected(() => {
    console.log('Connection reestablished.');
});

connection.start({
    transport: ['webSockets', 'longPolling'],
    reconnectInterval: 5000, //ms
    reconnectAttempts: 10, //次
});

2. 在后端配置中添加服务端重连设置：

services.AddSignalR(hubOptions =>
{
    hubOptions.EnableDetailedErrors = true;
    hubOptions.KeepAliveInterval = TimeSpan.FromSeconds(30);
    hubOptions.ClientTimeoutInterval = TimeSpan.FromSeconds(60);
})
.AddMessagePackProtocol(options =>
{
    options.SerializerOptions = MessagePackSerializerOptions.Standard.WithSecurity(MessagePackSecurity.UntrustedData);
    options.Resolver = ContractlessStandardResolver.Instance;
})
.AddRedis(options =>
{
    options.Configuration = "localhost:6379,abortConnect=false";
    options.InstanceName = "SignalR";
    options.ConfigurationOptions.ConnectTimeout = 1000;
    options.ConfigurationOptions.SyncTimeout = 1000;
    options.ConfigurationOptions.ResponseTimeout = 3000;
    options.ConfigurationOptions.ConnectRetry = 5;
    options.ConfigurationOptions.ConnectTimeout = 5000;
});