fix(transport/memory): Improve the memory transport, 4x speed

[jochumdev]

This PR improves the speed of memory transport by a margin of 4x.

Have fun with testing/monolith's :)

Thanks @Davincible for a lot of help and the pipe idea.

[jochumdev]

Go 1.19.1 benchmark results:

$ GOMAXPROCS=8 go test -v -benchmem -run=^$ -bench ^BenchmarkService1$ go-micro.dev/v4

memory-old+json:
BenchmarkService1-8         2540            437535 ns/op           18841 B/op        323 allocs/op

memory-old+protobuf:
BenchmarkService1-8         2668            395556 ns/op           16050 B/op        285 allocs/op

memory-new(gob)+json:
BenchmarkService1-8        19388             55618 ns/op           14701 B/op        211 allocs/op

memory-new(gob)+protobuf:
BenchmarkService1-8        28543             40749 ns/op           12076 B/op        175 allocs/op

memory-new(msgpack)+protobuf:
BenchmarkService1-8        13498             83545 ns/op           11532 B/op        177 allocs/op