Returns a copy of this duration with the specified duration _in standard 24 hour days added.
!(p)
The number of days is multiplied by 86400 to obtain the number of seconds to add.
This is based on the standard definition of a day as 24 hours.
!(p)
This instance is immutable and unaffected by this method call.
@param daysToAdd the days to add, positive or negative
@return a {@code Duration} based on this duration with the specified days added, not null
@throws ArithmeticException if numeric overflow occurs
Returns a copy of this duration with the specified duration _in standard 24 hour days added. !(p) The number of days is multiplied by 86400 to obtain the number of seconds to add. This is based on the standard definition of a day as 24 hours. !(p) This instance is immutable and unaffected by this method call.
@param daysToAdd the days to add, positive or negative @return a {@code Duration} based on this duration with the specified days added, not null @throws ArithmeticException if numeric overflow occurs