paust-team/shapleq: broker/broker.go; 58 LoC

Found a possible issue in [paust-team/shapleq](https://www.github.com/paust-team/shapleq) at [broker/broker.go](https://github.com/paust-team/shapleq/blob/475bb7fceb84cebdb8149e27ad1d03c95ee1fbb4/broker/broker.go#L270-L327)

Below is the message reported by the analyzer for this snippet of code. Beware that the analyzer only reports the first
issue it finds, so please do not limit your consideration to the contents of the below message.

> range-loop variable sc used in defer or goroutine at line 279

[Click here to see the code in its original context.](https://github.com/paust-team/shapleq/blob/475bb7fceb84cebdb8149e27ad1d03c95ee1fbb4/broker/broker.go#L270-L327)

Click here to show the 58 line(s) of Go which triggered the analyzer.

```go
for sc := range scCh {
txMsgCh := make(chan *message.QMessage)
streamMsgCh := make(chan *message.QMessage)
wg.Add(1)
go func() {
defer close(txMsgCh)
defer close(streamMsgCh)
defer wg.Done()

b.sessionMgr.AddSession(sc.session)
defer b.sessionMgr.RemoveSession(sc.session)

sc.session.Open()
defer sc.session.Close()

msgCh, errCh, err := sc.session.ContinuousRead(sc.ctx)
if err != nil {
return
}

for {
select {
case <-sc.ctx.Done():
return
case msg := <-msgCh:
if msg != nil {
if msg.Type() == message.TRANSACTION {
txMsgCh <- msg
} else if msg.Type() == message.STREAM {
streamMsgCh <- msg
}
}

case err := <-errCh:
if err != nil {
pqErr, ok := err.(pqerror.PQError)
if !ok {
sessionErrCh <- internals.SessionError{
PQError: pqerror.UnhandledError{ErrStr: err.Error()},
Session: sc.session,
CancelSession: sc.cancelSession}
} else {
sessionErrCh <- internals.SessionError{
PQError: pqErr,
Session: sc.session,
CancelSession: sc.cancelSession}
}
}
default:
}
runtime.Gosched()
}
}()

transactionalEvents <- internals.EventStream{sc.session, txMsgCh, sc.ctx, sc.cancelSession}
streamingEvents <- internals.EventStream{sc.session, streamMsgCh, sc.ctx, sc.cancelSession}
runtime.Gosched()
}

```

Leave a reaction on this issue to contribute to the project by classifying this instance as a **Bug** :-1:, **Mitigated** :+1:, or **Desirable Behavior** :rocket:
See the descriptions of the classifications [here](https://github.com/github-vet/rangeclosure-findings#how-can-i-help) for more information.

commit ID: 475bb7fceb84cebdb8149e27ad1d03c95ee1fbb4