Adds a specified number of milliseconds to the current DateTimeOffset object.
An object whose value is the sum of the date and time represented by the current DateTimeOffset object and the number of whole milliseconds represented by milliseconds.
The fractional part of the milliseconds parameter is the fractional part of a millisecond. For example, 4.5 is equivalent to 4 milliseconds and 5000 ticks, where one millisecond equals 10,000 ticks. However, milliseconds is rounded to the nearest millisecond; all values of .5 or greater are rounded up.
This method returns a new DateTimeOffset object. It does not modify the value of the current object by adding milliseconds to its date and time.
Because a DateTimeOffset object does not represent the date and time in a specific time zone, the DateTimeOffset.AddMilliseconds(double) method does not consider a particular time zone's adjustment rules when it performs date and time arithmetic.