maxInstanceCount property
The limit on the maximum number of function instances that may coexist at a given time.
In some cases, such as rapid traffic surges, Cloud Functions may, for a short period of time, create more instances than the specified max instances limit. If your function cannot tolerate this temporary behavior, you may want to factor in a safety margin and set a lower max instances value than your function can tolerate. See the Max Instances Guide for more details.
Implementation
core.int? maxInstanceCount;