SQLite requires that the authorizer callback not modify the database connection

that invoked it, which includes preparing and stepping statements. Methods that

would do so throw an error with code `ERR_INVALID_STATE` while the callback is

on the stack, including `database.prepare()`, `database.exec()`, the execution

methods of that connection's statements, iterators, and tag stores, and

`database.setAuthorizer()` itself. Other connections remain usable.

The callback can also be invoked from within `statement.run()`,

`statement.get()`, and similar methods, because SQLite may re-prepare a

statement during execution after a schema change.

Separately, a statement that is currently being executed cannot be reentered.

Calling `statement.close()` on it would free the virtual machine that is

running, and re-running it through `statement.run()`, `statement.get()`,

`statement.all()`, `statement.iterate()`, `iterator.next()`,

`iterator.return()`, or the equivalent tag store methods would reset that

virtual machine mid-execution. All of these throw an `ERR_INVALID_STATE` error

instead. This applies to any callback SQLite invokes during execution, such as a

user-defined function. Other statements on the connection remain usable.

Operations that touch no SQLite state stay available from the callback:

`sqlTagStore.clear()`, which only drops cached statements, and `next()` and

`return()` on an already-drained iterator, which keep returning

`{ done: true }`.