Function build_public_trade_id 

pub fn build_public_trade_id(
    trade_id: &str,
    block_rfq_id: Option<i64>,
    block_trade_id: Option<&str>,
    combo_id: Option<&str>,
) -> TradeId

Builds a [TradeId] for a Deribit public trade, prefixing the venue ID with the trade’s provenance when applicable.

Strategies that need to distinguish RFQ-, block-, or combo-origin trades from plain trades can pattern-match the prefix on the resulting TradeId. The raw Deribit trade_id is preserved after the prefix so correlation back to the venue is straightforward via a prefix strip.

Precedence (most specific wins): RFQ- > BLK- > COMBO- > unprefixed. Block RFQs are themselves block trades on Deribit, so the RFQ- tag is the stronger signal; combo trades executed as blocks are tagged BLK- since the block flow is the more important reconciliation signal.