title: GetByteArrayRegion in JNI
body: <p>The question is:
  Suppose I use the function:
  (* env) -> GetByteArrayRegion (env, array, 0, len, (jbyte *)buf);
  In this case, a certain number of bytes written from the array to the buf or vice versa? Maybe a simple question, but I'm confused. Help, please:. In the documentation is not found.</p>