Most efficient way to concat massive files together using Rust

Suppose there are ten 100MB files that need to be combined in a Linux filesystem. What is the most efficient way to concatenate these files together using Rust, avoiding the shell?

Update: the io::copy approach was recommended. It seems to be about 3x slower than simply \cat file1 file2 file3 ... > final\\ . Is this the best that Rust can do?