Added some documentation to the GridTransferInterface and GridTransfer

4 jobs for issue/document_gradtransfer in 34 minutes and 22 seconds (queued for 25 minutes and 10 seconds)
Status Job ID Name Coverage
  Test
passed #8775
debian:10 clang-6-libcpp-17

00:24:59

passed #8774
debian:10 gcc-8-17

00:17:34

passed #8776
debian:9 gcc-6-14

00:18:00

passed #8777
ubuntu:18.04 clang-6-17

00:23:22