add optional prepend to preInstructions method builder

[Taylor123]

With the recent need to calculate compute units by simulating the Transaction it's become desirable to prepend instructions to the preInstructions. Specifically instructions like ComputeBudgetProgram.setComputeUnitPrice and ComputeBudgetProgram.setComputeUnitLimit should be prepended to the preInstructions array after simulating the transaction.

[vercel]

@Taylor123 is attempting to deploy a commit to the coral-xyz Team on Vercel.

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[acheroncrypto]

Thanks!

With the recent need to calculate compute units by simulating the Transaction it's become desirable to prepend instructions to the preInstructions.

I don't think it would hurt to merge this, but can't we achieve this with tx.instructions.unshift()?

[Taylor123]

if you're using the MethodBuilder rpc method to send the TX, then mutating the tx from the transaction() method wouldn't work, right?

[acheroncrypto]

Sort of — it would require a bit more setup compared to what we can do with this PR.

Before we merge this, could you also note this change in the CHANGELOG?

[Taylor123]

@acheroncrypto added

[acheroncrypto]

Thank you!