Pseudo code would be something like:

sub save
{ my $self = shift;
  my $acs = Net::Cisco::ACS->new("hostname"=>"localhost");
  my $user = Net::Cisco::ACS::User->new("username"=>"foobar");
 $acs->create($user); # Blocking code
 # Calling create will take a few seconds
}

sub list 
{ my $self = shift;
  my $acs = Net::Cisco::ACS->new("hostname" => "localhost");
  my %users = $acs->users; # Blocking code
  # Calling users will take a few seconds
}
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I don't need to call the API at that specific time. My original approach was to flag the record in my local database as 'created' or 'modified' and run a background process to make sure the local database synchronizes all flagged records with the application using the API. The list method would then only read from the database and make adjustments in the database.