Add close async method

[terryds]

Hi! 👋

Firstly, thanks for your work on this project! 🙂

Today I used patch-package to patch [email protected] for the project I'm working on.

Here is the diff that solved my problem:

diff --git a/node_modules/duckdb-async/dist/duckdb-async.js b/node_modules/duckdb-async/dist/duckdb-async.js
index 4ec133d..2df2e65 100644
--- a/node_modules/duckdb-async/dist/duckdb-async.js
+++ b/node_modules/duckdb-async/dist/duckdb-async.js
@@ -54,6 +54,7 @@ function methodPromisify(methodFn) {
     return util.promisify((target, ...args) => methodFn.bind(target)(...args));
 }
 const connAllAsync = methodPromisify(duckdb.Connection.prototype.all);
+const connCloseAsync = methodPromisify(duckdb.Connection.prototype.close);
 const connArrowIPCAll = methodPromisify(duckdb.Connection.prototype.arrowIPCAll);
 const connExecAsync = methodPromisify(duckdb.Connection.prototype.exec);
 const connPrepareAsync = methodPromisify(duckdb.Connection.prototype.prepare);
@@ -87,6 +88,14 @@ class Connection {
         }
         return connAllAsync(this.conn, sql, ...args);
     }
+    async close() {
+        if (!this.conn) {
+          throw new Error("Connection.close: uninitialized connection");
+        }
+        await connCloseAsync(this.conn);
+        this.conn = null;
+        return;
+    }
     async arrowIPCAll(sql, ...args) {
         if (!this.conn) {
             throw new Error("Connection.arrowIPCAll: uninitialized connection");
diff --git a/node_modules/duckdb-async/src/duckdb-async.ts b/node_modules/duckdb-async/src/duckdb-async.ts
index 45aec96..8e6d947 100644
--- a/node_modules/duckdb-async/src/duckdb-async.ts
+++ b/node_modules/duckdb-async/src/duckdb-async.ts
@@ -73,6 +73,10 @@ const connUnregisterBufferAsync = methodPromisify<duckdb.Connection, void>(
   duckdb.Connection.prototype.unregister_buffer
 );
 
+const connCloseAsync = methodPromisify<duckdb.Connection, void>(
+  duckdb.Connection.prototype.close
+);
+
 export class Connection {
   private conn: duckdb.Connection | null = null;
 
@@ -100,6 +104,15 @@ export class Connection {
     });
   }
 
+  async close(): Promise<void> {
+    if (!this.conn) {
+      throw new Error("Connection.close: uninitialized connection");
+    }
+    await connCloseAsync(this.conn);
+    this.conn = null;
+    return;
+  }
+
   async all(sql: string, ...args: any[]): Promise<duckdb.TableData> {
     if (!this.conn) {
       throw new Error("Connection.all: uninitialized connection");

This issue body was partially generated by patch-package.