use 5.12.0;
package CowTime {
    use Moo;
    use Types::DateTime -all;
    has timestamp =>
        is => "ro",
        isa => DateTimeUTC->plus_coercions( Format['ISO8601'] ),
        coerce => 1;
    1;
};

my $original = "2019-12-07T00:07:40.587596283-05:00";
my $cowtime = CowTime->new( timestamp => $original );

say $original;
say $cowtime->timestamp->time_zone;
say $cowtime->timestamp->nanosecond;
say $cowtime->timestamp;

__END__
2019-12-07T00:07:40.587596283-05:00
2019-12-07T05:07:40
DateTime::TimeZone::UTC=HASH(0x7f9e85ba3cd0)
587596283