eth/backend.go
func (b *backendInstance) EthBalanceAt(ctx context.Context,
	owner common.Address) (*big.Int, error) {
	ctx2, cancel := b.addTimeout(ctx)
	defer cancel()

	return b.conn.ethClient().BalanceAt(ctx2, owner, nil)
}
func (b *backendInstance) EthBalanceAt(ctx context.Context,
	owner common.Address) (*big.Int, error) {
	ctx2, cancel := b.addTimeout(ctx)
	defer cancel()

	return b.conn.ethClient().BalanceAt(ctx2, owner, nil)
}
// EthBalanceAt returns the wei balance of the given account.