increase max feerate sanity check from 1000 to 2500

[Melvillian]

Back in Nov 2016 when we first set the maximum fee rate sanity check the average feerate for inclusion in 1-2 blocks was ~70 sat/byte and there was relatively low variability. Nowadays we're seeing an increase in variability, with the fee rates spiking to over ~1000 sat/byte.

We've had multiple customers trigger this "absurd fees" error when trying to build their transactions.

I think the current fee market warrants increasing this to a higher value. I think 2500 sat/byte is appropriate because it will be handle more than double the current largest spike we've seen, and it's roughly 10x what the average feerate has been for the past 10 months.

[dcousens]

Published as v3.3.1

Thanks @Melvillian.

For reference, users can set the maximum to something higher using the 2nd parameter maximumFeeRate of the TransactionBuilder constructor.

[dcousens]

it's roughly 10x what the average feerate has been for the past 10 months.

I think this should be our baseline generally.

The rationale for this feature is I'd rather have users submitting complaints about an Error thrown (which is easily resolved by upping the limit manually), instead of their software biting them to the tune of absurd fees from some accounting problem.

But I'm open to any opposing view points. 👍

[dcousens]

Had to fix the tests with 34df503