client: Clarify that WaitForReady will block for CONNECTING channels (#4477)
client: Clarify that WaitForReady will block for CONNECTING channels (#4477)


dfawley/grpc-go,dfawley/grpc-go,stanley-cheung/grpc-go,grpc/grpc-go,menghanl/grpc-go,stanley-cheung/grpc-go,menghanl/grpc-go,grpc/grpc-go