CalculatePoolExpectation determines how much of `reserveA` you would need to put into a pool to get the `disbursed` amount of `reserveB`.

CalculatePoolPayout calculates the amount of `reserveB` disbursed from the pool for a `received` amount of `reserveA` .

NewOrderBookGraph constructs an empty OrderBookGraph.

OrderBookGraph is an in-memory graph representation of all the offers in the Stellar ledger.

Path represents a payment path from a source asset to some destination asset.

OBGraph is an interface for orderbook graphs.