handle no content responses for otlptraces http exporter

exporters/otlp/otlptrace/otlptracehttp/client.go

@@ -166,7 +166,7 @@ func (d *client) UploadTraces(ctx context.Context, protoSpans []*tracepb.Resourc
 		}
 
 		switch resp.StatusCode {
-		case http.StatusOK:
+		case http.StatusOK, http.StatusNoContent:
 			// Success, do not retry.
 			// Read the partial success message, if any.
 			var respData bytes.Buffer

exporters/otlp/otlptrace/otlptracehttp/client_test.go

@@ -401,3 +401,30 @@ func TestPartialSuccess(t *testing.T) {
 	require.Contains(t, errs[0].Error(), "partially successful")
 	require.Contains(t, errs[0].Error(), "2 spans rejected")
 }
+
+func TestNoContent(t *testing.T) {
+	mcCfg := mockCollectorConfig{
+		InjectHTTPStatus: []int{204},
+	}
+	mc := runMockCollector(t, mcCfg)
+	defer mc.MustStop(t)
+	driver := otlptracehttp.NewClient(
+		otlptracehttp.WithEndpoint(mc.Endpoint()),
+		otlptracehttp.WithInsecure(),
+	)
+	ctx := context.Background()
+	exporter, err := otlptrace.New(ctx, driver)
+	require.NoError(t, err)
+	defer func() {
+		assert.NoError(t, exporter.Shutdown(context.Background()))
+	}()
+
+	errs := []error{}
+	otel.SetErrorHandler(otel.ErrorHandlerFunc(func(err error) {
+		errs = append(errs, err)
+	}))
+	err = exporter.ExportSpans(ctx, otlptracetest.SingleReadOnlySpan())
+	assert.NoError(t, err)
+
+	require.Equal(t, 0, len(errs))
+}