compareTo method
Compare accounts according to the following rules.
Signer accounts go first, and within them writeable accounts go first.
Non-Signer accounts go after, and within them the writeable accounts go first.
Implementation
@override
int compareTo(AccountMeta other) {
if (isSigner && !other.isSigner) return -1;
if (!isSigner && other.isSigner) return 1;
if (isWriteable && !other.isWriteable) return -1;
if (!isWriteable && other.isWriteable) return 1;
return 0;
}