IHPDFHeadlessRenderLifetime

The interface in HPDFHeadlessRenderAccess retains a graph-lifetime lease without owning the document or its PDF objects

function IsValid: Boolean;

See IsValid for the permanent-expiration contract

THPDFHeadlessDocument.GetRenderAccess supplies a unique live lease; reload, graph mutation, close or destruction permanently invalidates it before borrowed objects are released

Custom adapters that enable viewer states must supply a lease with the same guarantees and a new identity for every rebuilt graph; bare pointer equality is insufficient when allocation addresses are reused

Nil remains compatible with ordinary static rendering, but explicit viewer-state creation requires a valid lease