fix: wrong bytes written for conn when encrypting

conn's Write method returns the wrong number of bytes written when encryption is used. This is unnoticeable when the response is less than 4096 bytes but I encountered a panic when I was implementing /resource for snapshots from cameras. The panic was in bufio.Writer with the following stack trace.

2023/12/25 17:27:50 http: panic serving 192.168.107.191:50535: runtime error: slice bounds out of range [29400:28878]
goroutine 43 [running]:
net/http.(*conn).serve.func1()
        /home/dev/.go/src/net/http/server.go:1868 +0xb9
panic({0x812f60?, 0xc000028108?})
        /home/dev/.go/src/runtime/panic.go:920 +0x270
bufio.(*Writer).Write(0xc00043cc40, {0xc0002f6000?, 0x840139?, 0x4?})
        /home/dev/.go/src/bufio/bufio.go:689 +0x1aa
net/http.(*chunkWriter).Write(0xc0002c4040, {0xc0002f6000, 0x8000, 0x8000})
        /home/dev/.go/src/net/http/server.go:388 +0x106
bufio.(*Writer).Write(0xc0002b6300, {0xc0002f6000?, 0xc0002f6000?, 0x87?})
        /home/dev/.go/src/bufio/bufio.go:682 +0xea
net/http.(*response).write(0xc0002c4000, 0x8000, {0xc0002f6000, 0x8000, 0x8000}, {0x0, 0x0})
        /home/dev/.go/src/net/http/server.go:1648 +0x22a
net/http.(*response).Write(0xc0002b7ec0?, {0xc0002f6000?, 0x8000?, 0x8000?})
        /home/dev/.go/src/net/http/server.go:1606 +0x2a
io.copyBuffer({0x8e0940, 0xc0005107f0}, {0x8e0140, 0xc00030ad50}, {0xc0002f6000, 0x8000, 0x8000})
        /home/dev/.go/src/io/io.go:432 +0x1f4
io.CopyBuffer({0x8e0940?, 0xc0005107f0?}, {0x8e0140?, 0xc00030ad50?}, {0xc0002f6000?, 0x30?, 0x30?})
        /home/dev/.go/src/io/io.go:403 +0x36
net/http.(*response).ReadFrom(0xc0002c4000, {0x8e0140?, 0xc00030ad50})
        /home/dev/.go/src/net/http/server.go:588 +0x3f0
github.com/go-chi/chi/middleware.(*httpFancyWriter).ReadFrom(0xc0002b6380, {0x8e0140, 0xc00030ad50})
        /home/dev/go/pkg/mod/github.com/go-chi/chi@v1.5.4/middleware/wrap_writer.go:137 +0xa3
io.copyBuffer({0x7f4258153ed8, 0xc0002b6380}, {0x8e0140, 0xc00030ad50}, {0xc0002e1800, 0x400, 0x400})
        /home/dev/.go/src/io/io.go:416 +0x147
io.CopyBuffer({0x7f4258153ed8?, 0xc0002b6380?}, {0x8e0140?, 0xc00030ad50?}, {0xc0002e1800?, 0x10?, 0x10?})
        /home/dev/.go/src/io/io.go:403 +0x36
main.main.func1({0x7f4258150cf8, 0xc0002b6380}, 0xc00010a800)
        /home/dev/tmp/hkplay/main.go:77 +0x4d2
net/http.HandlerFunc.ServeHTTP(0x7c7bc0?, {0x7f4258150cf8?, 0xc0002b6380?}, 0xc000325cb5?)
        /home/dev/.go/src/net/http/server.go:2136 +0x29
github.com/go-chi/chi.(*Mux).routeHTTP(0xc0000ac540, {0x7f4258150cf8, 0xc0002b6380}, 0xc00010a800)
        /home/dev/go/pkg/mod/github.com/go-chi/chi@v1.5.4/mux.go:436 +0x1f4
net/http.HandlerFunc.ServeHTTP(0xc00010a700?, {0x7f4258150cf8?, 0xc0002b6380?}, 0x30?)
        /home/dev/.go/src/net/http/server.go:2136 +0x29
github.com/brutella/hap.NewServer.RequestLogger.func3.1({0x8e2fb0, 0xc0002c4000}, 0xc00010a700)
        /home/dev/go/pkg/mod/github.com/go-chi/chi@v1.5.4/middleware/logger.go:57 +0x16d
net/http.HandlerFunc.ServeHTTP(0x8e38c8?, {0x8e2fb0?, 0xc0002c4000?}, 0xb64f40?)
        /home/dev/.go/src/net/http/server.go:2136 +0x29
github.com/go-chi/chi.(*Mux).ServeHTTP(0xc0000ac540, {0x8e2fb0, 0xc0002c4000}, 0xc00010a600)
        /home/dev/go/pkg/mod/github.com/go-chi/chi@v1.5.4/mux.go:87 +0x331
net/http.serverHandler.ServeHTTP({0x8e1bb8?}, {0x8e2fb0?, 0xc0002c4000?}, 0x6?)
        /home/dev/.go/src/net/http/server.go:2938 +0x8e
net/http.(*conn).serve(0xc000262870, {0x8e3890, 0xc000189290})
        /home/dev/.go/src/net/http/server.go:2009 +0x5f4
created by net/http.(*Server).Serve in goroutine 1
        /home/dev/.go/src/net/http/server.go:3086 +0x5cb

brutella / hap

fix: wrong bytes written for conn when encrypting #51