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 Name Job ID Coverage
  Test
passed debian:10 clang-6-libcpp-17 #8775

00:24:59

passed debian:10 gcc-8-17 #8774

00:17:34

passed debian:9 gcc-6-14 #8776

00:18:00

passed ubuntu:18.04 clang-6-17 #8777

00:23:22