SV = PVIV(0x8150b10) at 0x814f6b4   <-- Can contain an IV and PV
  REFCNT = 1
  FLAGS = (IOK,pIOK)                <-- Only contains an IV
  IV = 123
  PV = 0x81623f0 "abc"\0
  CUR = 3
  LEN = 4
SV = PVIV(0x8150b10) at 0x814f6b4   <-- Can contain an IV and PV
  REFCNT = 1
  FLAGS = (POK,pPOK)                <-- Only contains a PV
  IV = 123
  PV = 0x81623f0 "123"\0
  CUR = 3
  LEN = 4