struct used by Cmd.map_*_batch commands
Fields
in_batch: u64,
start batch, NULL to start from beginning
out_batch: u64,
output: next start batch
keys: u64,
values: u64,
count: u32,
input/output: input: # of key/value elements output: # of filled elements
map_fd: fd_t,
elem_flags: u64,
flags: u64,