Here's some example C using one:

    bytesRead = read(fd, buf, BUF_SIZE - 1)

You read the from the file descriptor into the buffer. Just like in Go you read from a file into a byte array. Neither the file descriptor nor the file is conceptualized as a tool for reading. The file descriptor is merely an abstraction of the file, which extends the concept of "file" to include pipes, sockets, and other io.