enter
Runs block with this snapshot as the current read context on the calling thread.
The previous snapshot context is restored even when block throws. Writes made without an explicitly entered MutableSnapshot still use an automatic global transaction and do not change the values read through this pinned snapshot.
Return
the value returned by block
Parameters
block
synchronous work executed under this snapshot
Type Parameters
R
type of value returned by block
Throws
if this snapshot has already been disposed