set priv 1234
get priv
int(1234)
int(123)
object(C)#1 (2) {
  ["priv":"C":private]=>
  int(1234)
  ["pub"]=>
  int(123)
}
set priv 6789
get priv
int(6789)
int(678)
object(C)#2 (2) {
  ["priv":"C":private]=>
  int(6789)
  ["pub"]=>
  int(678)
}

******************************

__set foo
object(D)#3 (1) {
  ["foo":protected]=>
  NULL
}
__get foo
__set foo
object(D)#3 (1) {
  ["foo":protected]=>
  NULL
}
__get foo
__set foo
object(D)#3 (1) {
  ["foo":protected]=>
  NULL
}

******************************

object(E)#3 (1) {
  ["foo"]=>
  int(1)
}
__get foo
object(E)#3 (1) {
  ["foo"]=>
  int(1)
}
__get foo
object(E)#3 (1) {
  ["foo"]=>
  int(1)
}

******************************

__set foo
object(F)#3 (0) {
}
object(F)#3 (1) {
  ["foo"]=>
  int(1)
}
object(F)#3 (1) {
  ["foo"]=>
  int(1)
}