Stellar newbie here.
Inherited some code that imports
github.com/stellar/go/build. The usage is to sign a transaction. The signature is:
AddSignatureToTransaction(build.TransactionEnvelopeBuilder, signature byte, publicKey string)
Can someone help me with a clue for what method to use from
txnbuild? Is it
txnbuild.NewTransaction()? Or is there a missing piece about "envelopes" that needs to be injected?