Merge branch jrpc:master into master

benchmark_test.go

client.go

client_test.go

conn.go

constants_unix.go

constants_unix_nocgo.go

endpoints.go

errors.go

example/echo/main.go

example/subscription/main.go

go.mod

go.sum

handler.go

helper.go

http.go

http_client.go

http_test.go

ipc.go

jrpc.go

json.go