Avoid using 0 for fs-verity extension ID am: 4cf73820

        assertSigningBlockAlignedAndHasFullPages(signatureInfo);

        long signingBlockSize =

                signatureInfo.centralDirOffset - signatureInfo.apkSigningBlockOffset;

        long dataSize = apk.length() - signingBlockSize - ZIP_EOCD_CENTRAL_DIR_OFFSET_FIELD_SIZE;

        long dataSize = apk.length() - signingBlockSize;

        int[] levelOffset = calculateVerityLevelOffset(dataSize);

        if (treeOutput != null) {

        buffer.putLong(fileSize);           // original file size

        buffer.put((byte) 0);               // auth block offset, disabled here

        buffer.put((byte) 2);               // extension count

        buffer.put((byte) 2);               // authenticated extension count

        buffer.put((byte) 0);               // unauthenticated extension count

        buffer.put(salt);                   // salt (8 bytes)

        skip(buffer, 22);                   // reserved

            long signingBlockSize, long eocdOffset) {

        // Snapshot of the FSVerity structs (subject to change once upstreamed).

        //

        // struct fsverity_extension {

        //   __le16 length;

        //   u8 type;

        //   u8 reserved[5];

        // };

        //

        // struct fsverity_extension_elide {

        //   __le64 offset;

        //   __le64 length;

            // struct fsverity_extension #1

            final int kSizeOfFsverityElidedExtension = 16;

            buffer.putShort((short)  // total size of extension, padded to 64-bit alignment

                    (kSizeOfFsverityExtensionHeader + kSizeOfFsverityElidedExtension));

            buffer.put((byte) 0);    // ID of elide extension

            skip(buffer, 5);         // reserved

            // First field is total size of extension, padded to 64-bit alignment

            buffer.putInt(kSizeOfFsverityExtensionHeader + kSizeOfFsverityElidedExtension);

            buffer.putShort((short) 1);  // ID of elide extension

            skip(buffer, 2);             // reserved

            // struct fsverity_extension_elide

            buffer.putLong(signingBlockOffset);

                    + 8 // offset size

                    + ZIP_EOCD_CENTRAL_DIR_OFFSET_FIELD_SIZE;

            buffer.putShort((short) kTotalSize);

            buffer.put((byte) 1);    // ID of patch extension

            skip(buffer, 5);         // reserved

            buffer.putInt(kTotalSize);   // Total size of extension, padded to 64-bit alignment

            buffer.putShort((short) 2);  // ID of patch extension

            skip(buffer, 2);             // reserved

            // struct fsverity_extension_patch

            buffer.putLong(eocdOffset + ZIP_EOCD_CENTRAL_DIR_OFFSET_FIELD_OFFSET);  // offset