fix(core): Fixed handling of prematurely closed streams

The API changed since the early experimental versions of Node's 'http2', although this fix shouldn't
break anything since fetch-h2 depends on v10

Closes #18

lib/fetch.ts

@@ -306,13 +306,13 @@ async function fetchImpl(
 					} )
 				);
 
-				stream.on( "streamClosed", guard( ( errorCode: number ) =>
+				stream.on( "close", guard( ( ) =>
 				{
 					// We'll get an 'error' event if there actually is an
 					// error, but not if we got NGHTTP2_NO_ERROR.
 					// In case of an error, the 'error' event will be awaited
 					// instead, to get (and propagate) the error object.
-					if ( errorCode === NGHTTP2_NO_ERROR )
+					if ( stream.rstCode === NGHTTP2_NO_ERROR )
 						reject(
 							new AbortError( "Stream prematurely closed" ) );
 				} ) );

test/fetch-h2/index.ts

@@ -690,7 +690,6 @@ describe( "goaway", ( ) =>
 
 describe( "integrity", ( ) =>
 {
-
 	it( "handle and succeed on valid integrity", async ( ) =>
 	{
 		const { server, port } = await makeServer( );
@@ -735,3 +734,26 @@ describe( "integrity", ( ) =>
 		await server.shutdown( );
 	} );
 } );
+
+describe( "premature stream close", ( ) =>
+{
+	it( "handle and reject fetch operation", async ( ) =>
+	{
+		const { server, port } = await makeServer( );
+
+		const url = `http://localhost:${port}/prem-close`;
+
+		try
+		{
+			await fetch( url );
+			expect( false ).to.equal( true );
+		}
+		catch ( err )
+		{
+			expect( err.message ).to.contain( "Stream prematurely closed" );
+		}
+
+		await disconnectAll( );
+		await server.shutdown( );
+	} );
+} );

test/lib/server.ts

@@ -328,6 +328,10 @@ export class Server
 			ignoreError( ( ) => stream.write( "fghij" ) );
 			ignoreError( ( ) => stream.end( ) );
 		}
+		else if ( path.startsWith( "/prem-close" ) )
+		{
+			stream.close( );
+		}
 		else
 		{
 			const matched = ( this._opts.matchers || [ ] )