     func start() {
         let observerPointer = unsafeBitCast(self, to: UnsafeMutableRawPointer.self)
         sqlite3_set_authorizer(database.sqliteConnection, { (observerPointer, actionCode, cString1, cString2, cString3, cString4) -> Int32 in
+            // print("\(actionCode) \([cString1, cString2, cString3, cString4].flatMap { $0.map({ String(cString: $0) }) })")
+            
+            // https://www.sqlite.org/c3ref/set_authorizer.html:
+            //
+            // > Applications must always be prepared to encounter a NULL
+            // > pointer in any of the third through the sixth parameters of
+            // > the authorization callback.
             switch actionCode {
             case SQLITE_DROP_TABLE, SQLITE_DROP_TEMP_TABLE, SQLITE_DROP_TEMP_VIEW, SQLITE_DROP_VIEW, SQLITE_DETACH, SQLITE_ALTER_TABLE, SQLITE_DROP_VTABLE, SQLITE_CREATE_INDEX, SQLITE_CREATE_TEMP_INDEX, SQLITE_DROP_INDEX, SQLITE_DROP_TEMP_INDEX:
                 let observer = unsafeBitCast(observerPointer, to: StatementCompilationObserver.self)

                    return SQLITE_IGNORE
                }
            case SQLITE_UPDATE:
                let observer = unsafeBitCast(observerPointer, to: StatementCompilationObserver.self)
                observer.insertUpdateEventKind(tableName: String(cString: cString1!), columnName: String(cString: cString2!))
            case SQLITE_TRANSACTION:
                let observer = unsafeBitCast(observerPointer, to: StatementCompilationObserver.self)
                let action = UpdateStatement.TransactionStatementInfo.TransactionAction(rawValue: String(cString: cString1!))!
                observer.transactionStatementInfo = .transaction(action: action)
            case SQLITE_SAVEPOINT:
                let observer = unsafeBitCast(observerPointer, to: StatementCompilationObserver.self)
                let name = String(cString: cString2!)
                let action = UpdateStatement.TransactionStatementInfo.SavepointAction(rawValue: String(cString: cString1!))!
                observer.transactionStatementInfo = .savepoint(name: name, action: action)
            case SQLITE_FUNCTION:
                let functionName = String(cString: cString2!)
                if functionName.uppercased() == "COUNT" {
                    // As soon as a request uses the COUNT function, we don't
                    // know which table is involved. For example, the

                }
                observer.invalidatesDatabaseSchemaCache = true
            case SQLITE_READ:
                guard let tableName = cString1.map({ String(cString: $0) }) else { return SQLITE_OK }
                guard let columnName = cString2.map({ String(cString: $0) }) else { return SQLITE_OK }
                let observer = unsafeBitCast(observerPointer, to: StatementCompilationObserver.self)
                observer.selectionInfo.insert(column: columnName, ofTable: tableName)
            case SQLITE_INSERT:
                guard let tableName = cString1.map({ String(cString: $0) }) else { return SQLITE_OK }
                let observer = unsafeBitCast(observerPointer, to: StatementCompilationObserver.self)
                observer.databaseEventKinds.append(.insert(tableName: tableName))
            case SQLITE_DELETE:
                guard let tableName = cString1.map({ String(cString: $0) }) else { return SQLITE_OK }
                let observer = unsafeBitCast(observerPointer, to: StatementCompilationObserver.self)
                if tableName != "sqlite_master" && !observer.isDropTableStatement {
                    observer.databaseEventKinds.append(.delete(tableName: tableName))
                    // Prevent [truncate optimization](https://www.sqlite.org/lang_delete.html#truncateopt)
