Cannot re-calling relay_header anymore.

[hackfisher]

darwinia-network/darwinia#214

So the proof and relay tools need to be fixed and updated, especially after child process get killed.

[clearloop]

We can relay one header for once, in cmd-tools, the second time we trying to relay a same header which is on darwinia, will raise an error at

darwinia-offchain-tools/cmd-tools/src/utils.ts

Line 91 in d0548c5

const err = `${doc.name}.${doc.section} - ${doc.documentation.join(" ")}`;

: telling you header exists

---

This will not happen

This will not happen in cmd-tools:

• in static mode proof tests, cmd-tools will reset a header before we relay the new one
• in dynamic mode proof tests, cmd-tools will relay header based on the bestheaderhash on darwinia
• in relay service, cmd-tools will check the bestheaderhash and auto-restart when this happens