grpc H2UnsentResponse LeakSanitizer: detected memory leaks

[hpsdy]

Describe the bug (描述bug)
asan 压测，报h2协议brpc::policy::H2UnsentResponse::New内存泄漏

To Reproduce (复现方法)
brpc1.8.0，h2:grpc协议。编译选项加上-fsanitize=address -fno-common，编译静态链接asan。

Expected behavior (期望行为)
期望不报任何异常错误。

Versions (各种版本)
OS: Linux bae12e6ce16f 5.4.139-1.el7.elrepo.x86_64 #1 SMP Sat Aug 7 08:29:46 EDT 2021 x86_64 x86_64 x86_64 GNU/Linux
Compiler: clang version 10.0.0-4ubuntu1
brpc: 1.8.0
protobuf: v3.20.0

Additional context/screenshots (更多上下文/截图)

[hpsdy]

有人么？

[chenBright]

brpc/src/brpc/policy/http2_rpc_protocol.cpp

Lines 1687 to 1691 in d3c6854

	H2UnsentResponse::AppendAndDestroySelf(butil::IOBuf* out, Socket* socket) {
	#if defined(BRPC_PROFILE_H2)
	bvar::ScopedTimer<bvar::Adder<int64_t> > tm(g_append_response_time);
	#endif
	DestroyingPtr<H2UnsentResponse> destroy_self(this);

brpc/src/brpc/policy/http2_rpc_protocol.cpp

Lines 1672 to 1678 in d3c6854

	void H2UnsentResponse::Destroy() {
	for (size_t i = 0; i < _size; ++i) {
	_list[i].~Header();
	}
	this->~H2UnsentResponse();
	free(this);
	}

在Socket里会调AppendAndDestroySelf回收的。

压测场景下，出现内存泄漏，应该不止泄漏几百bytes吧。是不是进程退出的时候，server还在处理请求呢？