Cache Set() should return error instead of bool

[Furkan Türkal]

Sorry for the issue, i just saw GitHub Issues are deprecated. But unfortunately discuss.dgraph.io requires sign-in, in order to open an issue. Time is so valuable to create a issue on another site whereas source code is not there. I think this is bad practice.

Currently, Set() function returns bool:

func (c *Cache) Set(key, value interface{}, cost int64) bool

But shouldn't it be better if return an error instead of bool? If it returns false, I'll never know why it false. For what reason did it return false? etc.

[github-actions]

Use Discuss Issues for reporting issues about this repository.

[Furkan Türkal]

Sorry for pinging. :( Why not a creating dgraph-io-bot to move issues automatically there? :)
@karlmcguire @manishrjain