cleanup, tests

internal/rwpipe/api.go

internal/rwpipe/rwpipe.go

internal/rwpipe/rwpipe_test.go

pkg/rtmp/chunk/api.go

pkg/rtmp/chunk/chunk.go

pkg/rtmp/chunk/chunks.go

pkg/rtmp/chunk/read_test.go

pkg/rtmp/client.go

pkg/rtmp/connection/api.go

pkg/rtmp/connection/connection.go

pkg/rtmp/connection/connection_test.go

pkg/rtmp/handshake/echo_test.go

pkg/rtmp/handshake/keys.go

pkg/rtmp/handshake/keys_test.go

pkg/rtmp/handshake/rwpipe_test.go

pkg/rtmp/server.go