async await init support

Sources/SwiftSgml/Tag.swift

@@ -31,6 +31,12 @@ open class Tag {
     public convenience init(@TagBuilder _ builder: () -> [Tag]) {
         self.init(builder())
     }
+
+    /// initialize a new Tag with children using an async throwing builder
+    public convenience init(@TagBuilder _ builder: () async throws -> [Tag]) async throws {
+        self.init(try await builder())
+    }
+
 
     /// initialize a new Tag with some contents
     public convenience init(_ contents: String?) {

Tests/SwiftSgmlTests/TagTests.swift

@@ -23,4 +23,24 @@ final class TagTests: XCTestCase {
                             """)
     }
 
+    func testConvenienceAsyncTagInit() async throws {
+
+        func leaf() async throws -> Leaf {
+            Leaf("hello")
+        }
+
+        let root = try await Root {
+            try await leaf()
+        }
+        let doc = Document {
+            root
+        }
+
+        XCTAssertEqual(DocumentRenderer().render(doc), """
+                            <root>
+                                <leaf>hello</leaf>
+                            </root>
+                            """)
     }
+
+}