Fix: return pointer from constructors (#15)

Author: aopoltorzhicky

pkg/modules/printer/printer.go

@@ -3,6 +3,7 @@ package printer
 import (
 	"context"
 	"fmt"
+
 	"github.com/dipdup-net/indexer-sdk/pkg/modules"
 )
 
@@ -17,10 +18,10 @@ const InputName = "input"
 var _ modules.Module = (*Printer)(nil)
 
 // NewPrinter - constructor of printer structure
-func NewPrinter() Printer {
+func NewPrinter() *Printer {
 	p := Printer{BaseModule: modules.New("printer")}
 	p.CreateInput(InputName)
-	return p
+	return &p
 }
 
 // Close - gracefully stops module

pkg/modules/stopper/stopper.go

@@ -2,6 +2,7 @@ package stopper
 
 import (
 	"context"
+
 	"github.com/dipdup-net/indexer-sdk/pkg/modules"
 	"github.com/rs/zerolog/log"
 )
@@ -24,14 +25,14 @@ const (
 	InputName = "signal"
 )
 
-func NewModule(cancelFunc context.CancelFunc) Module {
+func NewModule(cancelFunc context.CancelFunc) *Module {
 	m := Module{
 		BaseModule: modules.New("stopper"),
 		stop:       cancelFunc,
 	}
 	m.CreateInput(InputName)
 
-	return m
+	return &m
 }
 
 // Start -