fixup for latest micro v4

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

opentracing.go

@@ -278,7 +278,7 @@ func (t *otTracer) startSpanFromContext(ctx context.Context, name string, opts .
 		opts = append(opts, ot.ChildOf(parentSpan.Context()))
 	}
 
-	md := metadata.New(1)
+	md := make(map[string]string, 1)
 
 	sp := t.tracer.StartSpan(name, opts...)
 	if err := sp.Tracer().Inject(sp.Context(), ot.TextMap, ot.TextMapCarrier(md)); err != nil {
@@ -311,7 +311,8 @@ func (t *otTracer) startSpanFromOutgoingContext(ctx context.Context, name string
 		var parentCtx ot.SpanContext
 
 		if ok && md != nil {
-			if spanCtx, err := t.tracer.Extract(ot.TextMap, ot.TextMapCarrier(md)); err == nil && ok {
+			smd := make(map[string]string, 1)
+			if spanCtx, err := t.tracer.Extract(ot.TextMap, ot.TextMapCarrier(smd)); err == nil && ok {
 				parentCtx = spanCtx
 			}
 		}
@@ -322,7 +323,7 @@ func (t *otTracer) startSpanFromOutgoingContext(ctx context.Context, name string
 	}
 
 	nmd := metadata.Copy(md)
-	smd := metadata.New(1)
+	smd := make(map[string]string, 1)
 
 	sp := t.tracer.StartSpan(name, opts...)
 	if err := sp.Tracer().Inject(sp.Context(), ot.TextMap, ot.TextMapCarrier(smd)); err != nil {
@@ -358,7 +359,8 @@ func (t *otTracer) startSpanFromIncomingContext(ctx context.Context, name string
 		var parentCtx ot.SpanContext
 
 		if ok && md != nil {
-			if spanCtx, err := t.tracer.Extract(ot.TextMap, ot.TextMapCarrier(md)); err == nil {
+			smd := make(map[string]string, 1)
+			if spanCtx, err := t.tracer.Extract(ot.TextMap, ot.TextMapCarrier(smd)); err == nil {
 				parentCtx = spanCtx
 			}
 		}
@@ -369,7 +371,7 @@ func (t *otTracer) startSpanFromIncomingContext(ctx context.Context, name string
 	}
 
 	nmd := metadata.Copy(md)
-	smd := metadata.New(1)
+	smd := make(map[string]string, 1)
 
 	sp := t.tracer.StartSpan(name, opts...)
 	if err := sp.Tracer().Inject(sp.Context(), ot.TextMap, ot.TextMapCarrier(smd)); err != nil {