fix(tls): leak BIO_METHOD singleton to avoid use-after-free at exit (#1503)

Signed-off-by: yuchen.cc <yuchen.cc@alibaba-inc.com>

Author: yuchen0cc

net/security-context/tls-stream.cpp

@@ -392,12 +392,8 @@ class TLSSocketStream : public ForwardSocketStream {
 
 #endif
 
-    struct BIOMethodDeleter {
-        void operator()(BIO_METHOD* ptr) { BIO_meth_free(ptr); }
-    };
-
     static BIO_METHOD* BIO_s_sockstream() {
-        static std::unique_ptr<BIO_METHOD, BIOMethodDeleter> meth([] {
+        static BIO_METHOD* const meth = [] {
             auto m = BIO_meth_new(BIO_TYPE_SOURCE_SINK, "BIO_PHOTON_SOCKSTREAM");
             BIO_meth_set_write(m, &TLSSocketStream::ssbio_bwrite);
             BIO_meth_set_read(m, &TLSSocketStream::ssbio_bread);
@@ -406,8 +402,8 @@ class TLSSocketStream : public ForwardSocketStream {
             BIO_meth_set_create(m, &TLSSocketStream::ssbio_create);
             BIO_meth_set_destroy(m, &TLSSocketStream::ssbio_destroy);
             return m;
-        }());
-        return meth.get();
+        }();
+        return meth;
     }
 
     static ISocketStream* get_bio_sockstream(BIO* b) {