wallet race condition where coins are double-spent

[pinheadmz]

h/t @turbomaze

Issue sounds a lot like bcoin-org/bcoin#914 but that patch didn't solve.

• Are there multiple places where a TX is created and funded in the wallet in hsd requiring more locks in different places?
• Is there a race condition due to the time it takes from tx funding -> txdb insertion? (If I recall, the tx goes through the mempool first before inserting into txdb) maybe the coins are not marked as spent until its too late.

[nodech]

This sounds like the issue solved by the PR: #845

writeLock mentioned in the PR bcoin-org/bcoin#914 is not related to the funding, it instead only applies to wallet entries itself, like: encrypt/decrypt, change account/add account etc.