def init(id, pubkey, overwrite: false, network: 'test')
      raise "File '#{path}' already exists" if File.exist?(path) && !overwrite
      raise "Invalid network name '#{network}'" unless network =~ /^[a-z]{4,16}$/
      FileUtils.mkdir_p(File.dirname(path))
      IO.write(path, "#{network}\n#{PROTOCOL}\n#{id}\n#{pubkey.to_pub}\n\n")
      @txns.flush
      @head.flush
    end
def init(id, pubkey, overwrite: false, network: 'test')
      raise "File '#{path}' already exists" if File.exist?(path) && !overwrite
      raise "Invalid network name '#{network}'" unless network =~ /^[a-z]{4,16}$/
      FileUtils.mkdir_p(File.dirname(path))
      IO.write(path, "#{network}\n#{PROTOCOL}\n#{id}\n#{pubkey.to_pub}\n\n")
      @txns.flush
      @head.flush
    end
Creates an empty wallet with the specified ID and public key.