fix: record rate doc section

[psankhe28]

Checklist

• A link to the issue/user story that the pull request relates to
• How to recreate the problem without the fix
• Design of the fix
• How to prove that the fix works
• Automated tests that prove the fix keeps on working
• Documentation - any JSDoc, website, or Stackoverflow answers?

Issue/User story

#1635

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Design of the fix

Validation of the fix

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What documentation has been provided for this pull request

[davidkel]

Not sure this really addresses the issue here and is also confusing.

1. For the text format

• we should just state that the value of i will start at zero, so the first line represents 0 transactions submitted. Each value in a line represents time in milliseconds from the start of the round

2. For the binary format

• The first entry length is the total number of transactions submitted (it isn't so far) as it's a final output
• remove the line that starts if no transactions have been submitted..... this is not correct
• the subsequent values (Uint32 values in Big Endian or Little Endian format) represent time in milliseconds from the start of the round. Each entry corresponds to the number of transactions submitted starting from 0