final var groupRecipients = recipients.stream()
.filter(r -> r instanceof RecipientIdentifier.Group)
.map(RecipientIdentifier.Group.class::cast)
- .map(g -> g.groupId)
+ .map(RecipientIdentifier.Group::groupId)
.collect(Collectors.toList());
for (final var groupId : groupRecipients) {
timestamp = groupHandler.apply(groupId.serialize());