sharding

Description

When running Lighthouse in a shell pipeline it fails to exit gracefully because of the lack of signal handler for SIGPIPE. I noticed that my Lighthouse nodes wouldn't shutdown gracefully from my runner script, and it took a bit of digging to find the cause.

This command reproduces the issue (bash assumed):

$ lighthouse bn --network pyrmont |& tee -a pyrmont_bn.

• Introduce and implement circuit breaker pattern for weaver

At least this util is dead code and could be removed https://github.com/ChainSafe/lodestar/blob/master/packages/lodestar/src/util/io.ts

It would be nice to run ts-prune on each package of the monorepo to find and delete dead code

recently CI failed many times testing cluster because of port already used, which can be very annoying.