Add async APIs for shutting down the databases (#614)

Sources/FluentKit/Database/Database.swift

@@ -57,6 +57,13 @@ extension Database {
 public protocol DatabaseDriver: Sendable {
     func makeDatabase(with context: DatabaseContext) -> any Database
     func shutdown()
+    func shutdownAsync() async
+}
+
+public extension DatabaseDriver {
+    func shutdownAsync() async {
+        shutdown()
+    }
 }
 
 public protocol DatabaseConfiguration: Sendable {

Sources/FluentKit/Database/Databases.swift

@@ -141,6 +141,7 @@ public final class Databases: @unchecked Sendable { // @unchecked is safe here;
         self.lock.withLock { Set(self.configurations.keys) }
     }
 
+    @available(*, noasync, message: "Drivers may call wait() and should not be used in an async context", renamed: "shutdownAsync()")
     public func shutdown() {
         self.lock.withLockVoid {
             for driver in self.drivers.values {
@@ -149,6 +150,20 @@ public final class Databases: @unchecked Sendable { // @unchecked is safe here;
             self.drivers = [:]
         }
     }
+
+    public func shutdownAsync() async {
+        var driversToShutdown: [any DatabaseDriver] = []
+
+        self.lock.withLockVoid {
+            for driver in self.drivers.values {
+                driversToShutdown.append(driver)
+            }
+            self.drivers = [:]
+        }
+        for driver in driversToShutdown {
+            await driver.shutdownAsync()
+        }
+    }
 
     private func _requireConfiguration(for id: DatabaseID) -> any DatabaseConfiguration {
         guard let configuration = self.configurations[id] else {