how to build multiple sliding windows from xts object using rollapply function

I have a matrix with two columns where each column is a variable. I'm building two sliding windows of size 3

data <- matrix(1:20,ncol = 2, dimnames = list(NULL, c("var1","var2")))> data      var1 var2 [1,]    1   11 [2,]    2   12 [3,]    3   13 [4,]    4   14 [5,]    5   15 [6,]    6   16 [7,]    7   17 [8,]    8   18 [9,]    9   19[10,]   10   20> rollapplyr(data, 3, c)     [,1] [,2] [,3] [,4] [,5] [,6][1,]    1    2    3   11   12   13[2,]    2    3    4   12   13   14[3,]    3    4    5   13   14   15[4,]    4    5    6   14   15   16[5,]    5    6    7   15   16   17[6,]    6    7    8   16   17   18[7,]    7    8    9   17   18   19[8,]    8    9   10   18   19   20

But when I try to do the same with the xtc object I get an error

library(xts) data_xts <- xts(data, Sys.time()+1:10) rollapplyr(data_xts, 3, c)Error in array(ans, c(len.a%/%d2, d.ans), if (!is.null(names(dn.ans)) ||  :   length of 'dimnames' [1] not equal to array extent