Describe the push-based inbound oracle pattern: its problem, solution, and main trade-off.

An off-chain component watches for relevant changes and proactively pushes them onto the chain, unprompted. Initiated off-chain — good for irregular data, but the chain must trust that off-chain source.

• Problem: A blockchain application must be supplied with outside knowledge, but the closed chain can't have it communicated in by itself.
• Solution: The oracle monitors off-chain state changes and forwards them to the chain as they happen — no on-chain request needed.
• Benefit: Scattered or irregularly-updated data is proactively delivered; the contract needs no ability to search or poll for it, and the oracle can pre-check the data before submitting (helpful, given the chain's limited compute).
• Drawback: It isn't triggered or deployed on the chain, so data provision depends entirely on an off-chain (often non-distributed) application. To poison the chain, an adversary only has to compromise that single off-chain source — a concentrated attack surface.

Go deeper:

• Foundational Oracle Patterns (Mühlberger et al., arXiv) — the push-based inbound pattern: proactive delivery of irregular data and its single-source risk.