The country calling code for this number, as defined by the International
Telecommunication Union (ITU). For example, this would be 1 for NANPA
countries, and 33 for France.
Extension is not standardized in ITU recommendations, except for being
defined as a series of numbers with a maximum length of 40 digits. It is
defined as a string here to accommodate for the possible use of a leading
zero in the extension (organizations have complete freedom to do so, as
there is no standard defined). Other than digits, some other dialling
characters such as "," (indicating a wait) may be stored here.
In some countries, the national (significant) number starts with one or
more "0"s without this being a national prefix or trunk code of some kind.
For example, the leading zero in the national (significant) number of an
Italian phone number indicates the number is a fixed-line number. There
have been plans to migrate fixed-line numbers to start with the digit two
since December 2000, but it has not happened yet. See
http://en.wikipedia.org/wiki/%2B39 for more details.
The National (significant) Number, as defined in International
Telecommunication Union (ITU) Recommendation E.164, without any leading
zero. The leading-zero is stored separately if required, since this is an
uint64 and hence cannot store such information. Do not use this field
directly: if you want the national significant number, call the
getNationalSignificantNumber method of PhoneNumberUtil.
The carrier selection code that is preferred when calling this phone number
domestically. This also includes codes that need to be dialed in some
countries when calling from landlines to mobiles or vice versa. For
example, in Columbia, a "3" needs to be dialed before the phone number
itself when calling from a mobile phone to a domestic landline phone and
vice versa.
This field is used to store the raw input string containing phone numbers
before it was canonicalized by the library. For example, it could be used
to store alphanumerical numbers such as "1-800-GOOG-411".
