DartのMapを<String, dynamic>に変換するには？

// サンプルデータ
Map<String, bool> members = Map<String, bool>()
  ..putIfAbsent("userID1", () => true)
  ..putIfAbsent("userID2", () => true);
print(members);
// output:
// {userID1: true, userID2: true} 

var transMember = members.entries.map((member) {
  return <String, dynamic>{member.key: member.value};
});
print(transMember);
// output:
// ({userID1: true}, {userID2: true})