given a source stream, disconnect it from all of its downstream listeners (without closing the source or dest streams!)
var through =disconnect =source =dest =sourcedestsource // "got data"// returns `true` since there were dest pipessourcesourcereadable && sourcewritable // truedestreadable && destwritable // true
non-destructively disconnect all downstream destinations of
true if any destinations were disconnected, or
false if there
were no downstream listeners.