Removed Dimension KeyComparer I don't believe it was needed, as the implementation just used Dimension.Equals and Dimension.GetHashCode.  This is what the Default KeyComparer does: https://docs.microsoft.com/en-us/dotnet/api/system.collections.generic.equalitycomparer-1.default?view=netframework-4.7.2#remarks
Removed Dimension KeyComparer
I don't believe it was needed, as the implementation just used Dimension.Equals and Dimension.GetHashCode.  This is what the Default KeyComparer does: https://docs.microsoft.com/en-us/dotnet/api/system.collections.generic.equalitycomparer-1.default?view=netframework-4.7.2#remarks

Durwella/Durwella.Measurements