Panic on over UDF

I get an error:

panic: send on closed channel

goroutine 1744 [running]:
github.com/influxdata/kapacitor/edge.(*channelEdge).Collect(0xc004d4ddd0, 0x7f8ba5e7d7a8, 0xc2f52e6cf0, 0x407b03, 0xc00599e180)
/root/go/src/github.com/influxdata/kapacitor/edge/edge.go:58 +0xc3
github.com/influxdata/kapacitor/edge.(*streamStatsEdge).Collect(0xc003c43bc0, 0x7f8ba5e7d7a8, 0xc2f52e6cf0, 0x0, 0x0)
/root/go/src/github.com/influxdata/kapacitor/edge/stats.go:207 +0x4b
github.com/influxdata/kapacitor/edge.Forward(0xc0012d8260, 0x1, 0x1, 0x7f8ba5e7d7a8, 0xc2f52e6cf0, 0x0, 0x0)
/root/go/src/github.com/influxdata/kapacitor/edge/forwarding.go:104 +0x72
github.com/influxdata/kapacitor.(*UDFNode).runUDF.func2(0xc0029a77c0, 0xc006342c00)
/root/go/src/github.com/influxdata/kapacitor/udf.go:96 +0xc1
created by github.com/influxdata/kapacitor.(*UDFNode).runUDF
/root/go/src/github.com/influxdata/kapacitor/udf.go:93 +0x146

I use UDF without socket.
The handler closing i'm using the standard:
// Stop the handler gracefully.
func (a *objectHandler) Stop() {
close(a.agent.Responses)
}

The error occurs when processing a large number of tags at the time of changing the severity level.
Kapacitor version 1.5.2

Reproduce the UDF-without-socket case while processing many tags during a severity-level change. Read edge/edge.go, edge/stats.go, edge/forwarding.go, and udf.go, then inspect how the handler's Stop method closes Responses. Done means this shutdown path no longer panics with "send on closed channel".

Written by the indexing model from the issue text.