typedef enum { PETSC_DEVICE_CONTEXT_JOIN_DESTROY, PETSC_DEVICE_CONTEXT_JOIN_SYNC, PETSC_DEVICE_CONTEXT_JOIN_NO_SYNC } PetscDeviceContextJoinMode;
PETSC_DEVICE_CONTEXT_DESTROY - Destroy all incoming sub-contexts after join.
PETSC_CONTEXT_JOIN_SYNC - Synchronize incoming sub-contexts after join.
PETSC_CONTEXT_JOIN_NO_SYNC - Do not synchronize incoming sub-contexts after join.