fix(netconn): отдавать остаток очереди при закрытии пира

internal/netconn/pktpipe.go

@@ -85,6 +85,11 @@ func (p *packetPipe) ReadFrom(b []byte) (int, net.Addr, error) {
 		select {
 		case <-p.done:
 			return 0, nil, net.ErrClosed
+		case <-p.peer.done:
+			if n, ok := p.drain(b); ok {
+				return n, p.remote, nil
+			}
+			return 0, nil, net.ErrClosed
 		case <-changed:
 			continue
 		case <-timeout:
@@ -100,6 +105,20 @@ func (p *packetPipe) ReadFrom(b []byte) (int, net.Addr, error) {
 	}
 }
 
+func (p *packetPipe) drain(b []byte) (int, bool) {
+	select {
+	case buf, ok := <-p.rx:
+		if !ok {
+			return 0, false
+		}
+		n := copy(b, *buf)
+		p.pool.Put(buf)
+		return n, true
+	default:
+		return 0, false
+	}
+}
+
 func (p *packetPipe) readDeadline() (time.Time, <-chan struct{}) {
 	p.deadline.mu.Lock()
 	defer p.deadline.mu.Unlock()