readByteSync method
Synchronously reads a byte from stdin.
This call will block until a byte is available.
If at end of file, -1 is returned.
Implementation
external 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/Stdin/readByteSync.html