710a7136f9 rpc: Speedup getaddressesbylabel (João Barbosa)
Pull request description:
Fixes#15447. Same approach of #14984, this change avoids duplicate key check when building the JSON response in memory.
ACKs for commit 710a71:
MarcoFalke:
utACK 710a7136f9
ryanofsky:
utACK 710a7136f9. Just new comments and assert since last review.
Tree-SHA512: 77c95df9ff3793e348619aa070e6fd36df9da1b461d708ab146652cb3699f1a472ef6eb38dafdb8374375cbc97daef07635fcb0501961f167a023309513742e2