/** Read bytes into the given {@link ByteBuf} and return the amount. */
private int doReadBytes(ByteBuf byteBuf) throws Exception {
int writerIndex = byteBuf.writerIndex();
int localReadAmount;
if (byteBuf.hasMemoryAddress()) {
localReadAmount =
Native.readAddress(fd, byteBuf.memoryAddress(), writerIndex, byteBuf.capacity());
} else {
ByteBuffer buf = byteBuf.internalNioBuffer(writerIndex, byteBuf.writableBytes());
localReadAmount = Native.read(fd, buf, buf.position(), buf.limit());
}
if (localReadAmount > 0) {
byteBuf.writerIndex(writerIndex + localReadAmount);
}
return localReadAmount;
}
