go/src/io/fs/readfile.go

type ReadFileFS …

// ReadFile reads the named file from the file system fs and returns its contents.
// A successful call returns a nil error, not [io.EOF].
// (Because ReadFile reads the whole file, the expected EOF
// from the final Read is not treated as an error to be reported.)
//
// If fs implements [ReadFileFS], ReadFile calls fs.ReadFile.
// Otherwise ReadFile calls fs.Open and uses Read and Close
// on the returned [File].
func ReadFile(fsys FS, name string) ([]byte, error) { … }