The constructor shouldn't be doing extended work. I'd go with the following:

sub run {
   my ($self) = @_;
   ... do stuff with $self ...
}

# In user
Class->new(...)->run();
[download]

But, you could also go with either of the following:

sub run {
    my $class = shift;
    my $obj = $class->new(@_);
    ... do stuff with $obj ...
}


# In user
Class->run(...);
[download]

or

sub run {
    my $class = shift;
    $class->new(@_)->_run();
}

sub _run {
   my ($self) = @_;
   ... do stuff with $self ...
}

# In user
Class->run(...);
[download]