Is there an easy way to obtain the flank range and the flanked range in one GRanges object after calling flank()?

See the following example:

> gr1 <- GRanges(c(1,1),strand=Rle(c("+","-"),c(1,1)), IRanges(c(30,120), c(70,170)),mcols=data.frame(id=c("T1","T3")))
> gr1
GRanges object with 2 ranges and 1 metadata column:
      seqnames     ranges strand | mcols.id
         <Rle>  <IRanges>  <Rle> | <factor>
  [1]        1 [ 30,  70]      + |       T1
  [2]        1 [120, 170]      - |       T3
  -------
  seqinfo: 1 sequence from an unspecified genome; no seqlengths

flank(gr1, 10) 

> flank(gr1, 10)
GRanges object with 2 ranges and 1 metadata column:
      seqnames     ranges strand | mcols.id
         <Rle>  <IRanges>  <Rle> | <factor>
  [1]        1 [ 20,  29]      + |       T1
  [2]        1 [171, 180]      - |       T3
  -------
  seqinfo: 1 sequence from an unspecified genome; no seqlengths

What I would like to get is:

> gr1
GRanges object with 2 ranges and 1 metadata column:
      seqnames     ranges strand | mcols.id
         <Rle>  <IRanges>  <Rle> | <factor>
  [1]        1 [ 20,  70]      + |       T1
  [2]        1 [120, 180]      - |       T3
  -------
  seqinfo: 1 sequence from an unspecified genome; no seqlengths

Any hint on this is greatly appreciated!

Try resize():

> resize(gr1, width=width(gr1) + 10, fix="end")
GRanges object with 2 ranges and 1 metadata column:
      seqnames     ranges strand | mcols.id
         <Rle>  <IRanges>  <Rle> | <factor>
  [1]        1 [ 20,  70]      + |       T1
  [2]        1 [120, 180]      - |       T3
  -------
  seqinfo: 1 sequence from an unspecified genome; no seqlengths

Valerie