feat(protocol): allow override of dial func

reach/client/protocol/v2/protocol.go

@@ -15,6 +15,7 @@ const compatibleVersionConstraint = ">= 32"
 
 type Protocol struct {
 	logger logger.Logger
+	dial   protocol.DialFunc
 }
 
 // Available implements protocol.Protocol.
@@ -50,7 +51,11 @@ func (p *Protocol) Identifier() protocol.Identifier {
 
 // Operations implements protocol.Protocol.
 func (p *Protocol) Operations(addr string) protocol.Operations {
-	return &Operations{addr: addr, logger: p.logger}
+	return &Operations{
+		dial:   p.dial,
+		addr:   addr,
+		logger: p.logger,
+	}
 }
 
 var _ protocol.Protocol = &Protocol{}