http2: expose writable stream state on compat response

Signed-off-by: Terry Chen <terry@example.com>

Author: Terry Chen

lib/internal/http2/compat.js

@@ -551,6 +551,10 @@ class Http2ServerResponse extends Stream {
     return this[kStream].writableHighWaterMark;
   }
 
+  get writableObjectMode() {
+    return this[kStream].writableObjectMode;
+  }
+
   get writableFinished() {
     return this[kStream].writableFinished;
   }
@@ -559,6 +563,10 @@ class Http2ServerResponse extends Stream {
     return this[kStream].writableLength;
   }
 
+  get writableNeedDrain() {
+    return this[kStream].writableNeedDrain;
+  }
+
   set statusCode(code) {
     code |= 0;
     if (code >= 100 && code < 200)

test/parallel/test-http2-res-writable-properties.js

@@ -7,11 +7,14 @@ const http2 = require('http2');
 const server = http2.createServer(common.mustCall((req, res) => {
   const hwm = req.socket.writableHighWaterMark;
   assert.strictEqual(res.writableHighWaterMark, hwm);
+  assert.strictEqual(res.writableObjectMode, res.stream.writableObjectMode);
+  assert.strictEqual(res.writableNeedDrain, res.stream.writableNeedDrain);
   assert.strictEqual(res.writableLength, 0);
   res.write('');
   const len = res.writableLength;
   res.write('asd');
   assert.strictEqual(res.writableLength, len + 3);
+  assert.strictEqual(res.writableNeedDrain, res.stream.writableNeedDrain);
   res.end();
   res.on('finish', common.mustCall(() => {
     assert.strictEqual(res.writableLength, 0);