As part of trying to make the inputs and outputs of the evm subcommands
more streamlined and aligned, this PR modifies how `evm t8n` manages
output-files.
Previously, we do a kind of wonky thing where between each transaction,
we invoke a `getTracer` closure. In that closure, we create a new
output-file, a tracer, and then make the tracer stream output to the
file. We also fiddle a bit to ensure that the file becomes properly
closed.
It is a kind of hacky solution we have in place. This PR changes it, so
that from the execution-pipeline point of view, we have just a regular
tracer. No fiddling with re-setting it or closing files.
That particular tracer, however, is a bit special: it takes care of
creating new files per transaction (in the tx-start-hook) and closing
(on tx-end-hook). Also instantiating the right type of underlying
tracer, which can be a json-logger or a custom tracer.
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Co-authored-by: Gary Rong <garyrong0905@gmail.com>