Energistics.Etp.v11.Datatypes.ChannelData.ChannelMetadataRecord.Uuid should be a string

[gklittlejohn]

This has been changed from a string to a Guid?. If an empty string or a string is received that is not formatted as a Guid deserialization fails as such this is potentially a breaking change.

Other objects in the ETP specification explicitly define a Uuid field as being a UUID but this is not specified for ChannelMetadataRecord.Uuid .