/// <summary>
/// Create new instance of <see cref="PropertySet"/>
/// </summary>
/// <param name="objectSchema">Object schema.</param>
protected PropertySet(ObjectSchema objectSchema)
{
objectSchema.ThrowIfNull(nameof(objectSchema));
this.objectSchema = objectSchema;
this.firstClassProperties = new List <PropertyDefinition>();
this.firstClassProperties.Add(EntityObjectSchema.Id);
this.requestedProperties = new List <PropertyDefinition>();
}