RedisGrainStorage.ReadStateAsync() should use Array.Length instead of Linq.Enumerable.Count()

[f-i-x-7]

There is a possibility for micro perf improvement by replacing this line:

Orleans.Redis/src/Orleans.Persistence.Redis/RedisGrainStorage.cs

Line 124 in 1de3c47

if (hashEntries.Count() == 2)

to this:

if (hashEntries.Length == 2)

hashEntries is an array, so this is technically possible, and it should benefit by eliminating virtual call to ICollection<T>.Count that is called by Linq.Enumerable.Count() under the hood (in theory it is possible that due to several inlines made by JIT a possibility for guarded devirtualization can occur, but I think it is better to reduce JIT work anyway and just access Length directly).

This is very simple change, so if you are interested in it, I could submit a PR.