readByteSync method
Synchronously reads a single byte from the file.
If end-of-file has been reached -1 is returned.
Throws a FileSystemException if the operation fails.
Implementation
int readByteSync();© 2012 the Dart project authors
Licensed under the BSD 3-Clause "New" or "Revised" License.
https://api.dart.dev/stable/2.18.5/dart-io/RandomAccessFile/readByteSync.html