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/haivision/srtgo/write.go

@@ -0,0 +1,55 @@
+package srtgo
+
+/*
+#cgo LDFLAGS: -lsrt
+#include <srt/srt.h>
+
+int srt_sendmsg2_wrapped(SRTSOCKET u, const char* buf, int len, SRT_MSGCTRL *mctrl, int *srterror, int *syserror)
+{
+	int ret = srt_sendmsg2(u, buf, len, mctrl);
+	if (ret < 0) {
+		*srterror = srt_getlasterror(syserror);
+	}
+	return ret;
+}
+
+*/
+import "C"
+import (
+	"errors"
+	"syscall"
+	"unsafe"
+)
+
+func srtSendMsg2Impl(u C.SRTSOCKET, buf []byte, msgctrl *C.SRT_MSGCTRL) (n int, err error) {
+	srterr := C.int(0)
+	syserr := C.int(0)
+	n = int(C.srt_sendmsg2_wrapped(u, (*C.char)(unsafe.Pointer(&buf[0])), C.int(len(buf)), msgctrl, &srterr, &syserr))
+	if n < 0 {
+		srterror := SRTErrno(srterr)
+		if syserr < 0 {
+			srterror.wrapSysErr(syscall.Errno(syserr))
+		}
+		err = srterror
+		n = 0
+	}
+	return
+}
+
+// Write data to the SRT socket
+func (s SrtSocket) Write(b []byte) (n int, err error) {
+
+	//Fastpath:
+	if !s.blocking {
+		s.pd.reset(ModeWrite)
+	}
+	n, err = srtSendMsg2Impl(s.socket, b, nil)
+
+	for {
+		if !errors.Is(err, error(EAsyncSND)) || s.blocking {
+			return
+		}
+		s.pd.wait(ModeWrite)
+		n, err = srtSendMsg2Impl(s.socket, b, nil)
+	}
+}