"Oneofthemostbasiclawsofawebapplicationisthattheclient,nottheserver,mustinitiateanycommunicationbetweenthetwo.Thereareanumberofcommon–usecaseswhere,ideally,theserverwouldliketotalktotheclient—dashboardsandmonitoringapps,chatroomsandothercollaborations,andprogressreportsonlon