panic: nil pointer of map

[bo-er]

Here is the error message, it seems that line 84: stream.MetaHeaders[key] = value is the root casue.

[root@udp1 ~]# ./main -p 5700 -proto-path /root -proto-files ucore.proto
INFO[0000] Starting sniff ethernet packets at interface eth0 on port 5700
panic: assignment to entry in nil map

goroutine 52 [running]:
github.com/rmedvedev/grpcdump/internal/app/framereader.(*FrameReader).Read(0xc00011cef0, 0xc00012a080)
	/root/grpcdump/internal/app/framereader/framereader.go:84 +0x62d
github.com/rmedvedev/grpcdump/internal/app/httpparser.tryReadHttp2(0xc00012a080?, {0xc00011cdb0?, 0x4?}, 0x18614ac?, 0x0?)
	/root/grpcdump/internal/app/httpparser/httpparser.go:148 +0x86
github.com/rmedvedev/grpcdump/internal/app/httpparser.(*httpStream).run(0xc000112180)
	/root/grpcdump/internal/app/httpparser/httpparser.go:201 +0x81b
created by github.com/rmedvedev/grpcdump/internal/app/httpparser.(*httpStreamFactory).New
	/root/grpcdump/internal/app/httpparser/httpparser.go:60 +0x22a

So I'm about to fix it.