attach
Attaches this session on its owner thread.
A created or detached session becomes attached, and the first attach evaluates and reconciles the content once. Attachment starts a new frame lifetime, so the first frame after reattachment reruns the retained pipeline even when content and constraints are unchanged. Invalid lifecycle transitions leave state unchanged; content and reconciliation failures poison the session and perform cleanup before rethrowing the exact primary failure.
Throws
when called from the wrong thread, reentrantly, or from an invalid lifecycle state.
when content, reconciliation, lifecycle, or cleanup fails; the first failure remains primary with later distinct failures suppressed.