parquet-common/src/main/java/org/apache/parquet/io/DelegatingSeekableInputStream.java
static void readFullyHeapBuffer(InputStream f, ByteBuffer buf) throws IOException {
    readFully(f, buf.array(), buf.arrayOffset() + buf.position(), buf.remaining());
    buf.position(buf.limit());
  }
static void readFullyHeapBuffer(InputStream f, ByteBuffer buf) throws IOException {
    readFully(f, buf.array(), buf.arrayOffset() + buf.position(), buf.remaining());
    buf.position(buf.limit());
  }
Visible for testing