TestSenderInterceptor/after_RTP_packets is flaky

[mengelbart]

I have had this fail a couple of times now in unrelated PRs.

From CI:

--- FAIL: TestSenderInterceptor (4.91s)
    --- FAIL: TestSenderInterceptor/after_RTP_packets (0.10s)
        sender_interceptor_test.go:79: 
            	Error Trace:	D:/a/interceptor/interceptor/pkg/twcc/sender_interceptor_test.go:79
            	Error:      	Not equal: 
            	            	expected: []rtcp.PacketStatusChunk{(*rtcp.RunLengthChunk)(0xc000282108)}
            	            	actual  : []rtcp.PacketStatusChunk{(*rtcp.StatusVectorChunk)(0xc0002a8480), (*rtcp.StatusVectorChunk)(0xc0002a84b0)}
            	            	
            	            	Diff:
            	            	--- Expected
            	            	+++ Actual
            	            	@@ -1,7 +1,25 @@
            	            	-([]rtcp.PacketStatusChunk) (len=1) {
            	            	- (*rtcp.RunLengthChunk)({
            	            	+([]rtcp.PacketStatusChunk) (len=2) {
            	            	+ (*rtcp.StatusVectorChunk)({
            	            	   PacketStatusChunk: (rtcp.PacketStatusChunk) <nil>,
            	            	   Type: (uint16) 0,
            	            	-  PacketStatusSymbol: (uint16) 1,
            	            	-  RunLength: (uint16) 10
            	            	+  SymbolSize: (uint16) 1,
            	            	+  SymbolList: ([]uint16) (len=7) {
            	            	+   (uint16) 1,
            	            	+   (uint16) 2,
            	            	+   (uint16) 1,
            	            	+   (uint16) 2,
            	            	+   (uint16) 1,
            	            	+   (uint16) 2,
            	            	+   (uint16) 1
            	            	+  }
            	            	+ }),
            	            	+ (*rtcp.StatusVectorChunk)({
            	            	+  PacketStatusChunk: (rtcp.PacketStatusChunk) <nil>,
            	            	+  Type: (uint16) 0,
            	            	+  SymbolSize: (uint16) 1,
            	            	+  SymbolList: ([]uint16) (len=3) {
            	            	+   (uint16) 2,
            	            	+   (uint16) 1,
            	            	+   (uint16) 2
            	            	+  }
            	            	  })
            	Test:       	TestSenderInterceptor/after_RTP_packets