Constant CREATE_EVENTS_TABLE 

pub const CREATE_EVENTS_TABLE: &str = "
CREATE TABLE IF NOT EXISTS events (
    workflow_id TEXT NOT NULL,
    seq INTEGER NOT NULL,
    event BLOB NOT NULL,
    recorded_at TEXT NOT NULL,
    event_kind TEXT NOT NULL,
    is_queryable_event INTEGER NOT NULL,
    workflow_type TEXT,
    child_workflow_id TEXT,
    PRIMARY KEY (workflow_id, seq)
)";

Append-only workflow event table.