Adding lock value as parameter to lock()

[lilacdev]

Here is my idea. Not the best JS developper, perhaps this is dirty ;).

[coveralls]

Coverage decreased (-0.2%) to 99.758% when pulling 88f532c on netwoof:patch-2 into feab262 on mike-marcacci:master.

[mike-marcacci]

Hi @lilacdev, thanks for the PR! While there isn't technically a problem here, I'm a bit hesitant to make this change, since it opens up a very serious footgun: passing an insufficiently random valueOrCallback would cause some serious problems in real world uses, since multiple locks would have the same value. This could allow a partially acquired lock to invalidate a different, fully-acquired lock.

It would be safe if you were to, for example, use a nonrandom prefix to the value like `foo${Redlock.prototype._random()}`, but using "foo" by itself would have potentially very bad consequences, under very unpredictable conditions.

I'll continue to think about this, but in the meantime you can simply use the "private" method, _lock(resource, value, ttl, callback) with your prefixed random value.

[mike-marcacci]

I'm going to go ahead and close this, because I don't want to encourage dangerous patterns here (per my comment above). Let me know if you have a compelling use case that truly requires this.