SCPStatementXdr

union switch (SCPStatementType type)
{
case SCP_ST_PREPARE:
    struct
    {
        Hash quorumSetHash;       // D
        SCPBallot ballot;         // b
        SCPBallot* prepared;      // p
        SCPBallot* preparedPrime; // p'
        uint32 nC;                // c.n
        uint32 nH;                // h.n
    } prepare;
case SCP_ST_CONFIRM:
    struct
    {
        SCPBallot ballot;   // b
        uint32 nPrepared;   // p.n
        uint32 nCommit;     // c.n
        uint32 nH;          // h.n
        Hash quorumSetHash; // D
    } confirm;
case SCP_ST_EXTERNALIZE:
    struct
    {
        SCPBallot commit;         // c
        uint32 nH;                // h.n
        Hash commitQuorumSetHash; // D used before EXTERNALIZE
    } externalize;
case SCP_ST_NOMINATE:
    SCPNomination nominate;
}
pledges;