public int getCacheLength() {
        return cacheLength;
    }
Read a packet like in.readFully(bytes) does - but do not throw an exception and return false if nothing
could be read at all.
@param in the input stream
@param bytes the array to be filled with data
@return true if a packet as been read, false if the stream was at EOF right at the beginning.
@throws IOException When a problem occurs, especially EOFException when there's an EOF in the middle of the packet.
src/main/java/com/notnoop/apns/internal/ApnsConnectionImpl.java