minus method
减一个值 并发射
Implementation
int? minus([int value = 1]) {
if (_subject.isClosed) {
L.w('IO在close状态下请求发送数据');
return null;
}
int result;
if (_remainder != null) {
result = (latest - value).remainder(_remainder!);
if (_min != null) {
result = math.max(_min!, result);
}
} else if (_min != null) {
result = math.max(latest - value, _min!);
} else {
result = latest - value;
}
_subject.add(result);
return result;
}