by the time you get this assignment I would have left vs By the time you get this assignment I am going to left

Some examples from the web:

• This applies in the times between assignments as well.
• This isn't a part-time assignment.
• And both of those times on assignments with me...
• Those measures shall be taken no later than at the time of the payout or at the time of the assignment, in whole or in part, of the policy.
• For part-time assignments under point (a) of paragraph 4, the employer shall issue a document for each employee setting out the percentage of time to be worked on the operation.
• Staff costs related to individuals who work on part-time assignment on the operation, shall be calculated as either:
• For part-time assignments under point (b) of paragraph 4, the reimbursement of staff costs shall be calculated on an hourly rate basis determined either by:
• By the time you read this letter I would be gone. I took part in the contest to accompany you.
• I would have waited for you, but by the time you were born, I was middle-aged.
• At the time the assignment of the contracts to ABB was concluded, the shipyard's order book was virtually full, which left the yard with little flexibility for eventually advancing production of the vessels in the face of the new requirements of the ship owner.
• Why did I get this assignment?
• You're just in time to receive your assignments.
• - is unlawful, unjustified and arbitrary for failing to take account of the fact that, at the time of the assignment, the medical committee had recognised that the applicant was unfit for service until 31 December 2004;
• The City of Mikkeli estimates the market value of the land at the time of the assignment at EUR 300000. According to Finland the costs of levelling the site amounted to FIM 2 million (EUR 336376).
• Winston, I think it's time for a new assignment.
• This time I was on assignment for a magazine, but again worked closely with MSF.
• Ms. Reed has spent a lot of time on assignment in the Middle East.
• Hopefully we'll be done by the time you guys land.
• - No, they're mostly evaporated - by the time you get here.
• By the time you receive this message, I should be in Brazil.

Some examples from the web:

• This applies in the times between assignments as well.
• This isn't a part-time assignment.
• And both of those times on assignments with me...
• Those measures shall be taken no later than at the time of the payout or at the time of the assignment, in whole or in part, of the policy.
• For part-time assignments under point (a) of paragraph 4, the employer shall issue a document for each employee setting out the percentage of time to be worked on the operation.
• Staff costs related to individuals who work on part-time assignment on the operation, shall be calculated as either:
• For part-time assignments under point (b) of paragraph 4, the reimbursement of staff costs shall be calculated on an hourly rate basis determined either by:
• At the time the assignment of the contracts to ABB was concluded, the shipyard's order book was virtually full, which left the yard with little flexibility for eventually advancing production of the vessels in the face of the new requirements of the ship owner.
• Why did I get this assignment?
• You're just in time to receive your assignments.
• - is unlawful, unjustified and arbitrary for failing to take account of the fact that, at the time of the assignment, the medical committee had recognised that the applicant was unfit for service until 31 December 2004;
• The City of Mikkeli estimates the market value of the land at the time of the assignment at EUR 300000. According to Finland the costs of levelling the site amounted to FIM 2 million (EUR 336376).
• This time I was on assignment for a magazine, but again worked closely with MSF.
• Winston, I think it's time for a new assignment.
• Ms. Reed has spent a lot of time on assignment in the Middle East.
• By the time you arrived, the water was gone.
• Granger, we'll have addresses to you by the time you get there.
• By the time you're back, they'll be finished.
• Be morning by the time you get to Jackson.
• I'll be gone by the time you get here.