SmartPtr: Support load test for source by srs-bench. v6.0.130 (#4097)

1. Add live benchmark support in srs-bench, which only connects and
disconnects without any media transport, to test source creation and
disposal and verify source memory leaks.
2. SmartPtr: Support cleanup of HTTP-FLV stream. Unregister the HTTP-FLV
handler for the pattern and clean up the objects and resources.
3. Support benchmarking RTMP/SRT with srs-bench by integrating the gosrt
and oryx RTMP libraries.
4. Refine SRT and RTC sources by using a timer to clean up the sources,
following the same strategy as the Live source.

---------

Co-authored-by: Haibo Chen <495810242@qq.com>
Co-authored-by: Jacob Su <suzp1984@gmail.com>

trunk/3rdparty/srs-bench/vendor/github.com/mattn/go-pointer/pointer.go

@@ -0,0 +1,57 @@
+package pointer
+
+// #include <stdlib.h>
+import "C"
+import (
+	"sync"
+	"unsafe"
+)
+
+var (
+	mutex sync.RWMutex
+	store = map[unsafe.Pointer]interface{}{}
+)
+
+func Save(v interface{}) unsafe.Pointer {
+	if v == nil {
+		return nil
+	}
+
+	// Generate real fake C pointer.
+	// This pointer will not store any data, but will bi used for indexing purposes.
+	// Since Go doest allow to cast dangling pointer to unsafe.Pointer, we do rally allocate one byte.
+	// Why we need indexing, because Go doest allow C code to store pointers to Go data.
+	var ptr unsafe.Pointer = C.malloc(C.size_t(1))
+	if ptr == nil {
+		panic("can't allocate 'cgo-pointer hack index pointer': ptr == nil")
+	}
+
+	mutex.Lock()
+	store[ptr] = v
+	mutex.Unlock()
+
+	return ptr
+}
+
+func Restore(ptr unsafe.Pointer) (v interface{}) {
+	if ptr == nil {
+		return nil
+	}
+
+	mutex.RLock()
+	v = store[ptr]
+	mutex.RUnlock()
+	return
+}
+
+func Unref(ptr unsafe.Pointer) {
+	if ptr == nil {
+		return
+	}
+
+	mutex.Lock()
+	delete(store, ptr)
+	mutex.Unlock()
+
+	C.free(ptr)
+}