Packet recording file format
----------------------------

struct FileFormat {
    struct Header header;
    struct Body packets[];
};

struct Header { // 1024 bytes
    char magic[4];          // "PKT\0"
    uint16_t version;       // File format version; is 0 right now.

    unsigned float time;    // time when recording started
    uint32_t accountID;
    uint32_t charID;
    char fieldName[20];
    char charName[25];
    // Everything else in the header is reserved for future usage.
}

struct Body {
    unsigned double time;
    uint16_t data_len;
    char data[data_len];
}
