Implement internal spanner stream exchanges method

[jcorilla]

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[tristanvuong2021]

Reviewed 1 of 3 files at r2, 4 of 4 files at r3, all commit messages.
Reviewable status: all files reviewed, 1 unresolved discussion (waiting on @jcorilla)

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src/main/kotlin/org/wfanet/measurement/kingdom/service/internal/testing/ExchangesServiceTest.kt line 283 at r3 (raw file):

  @Test
  fun `streamExchange respects limit`(): Unit = runBlocking {
    val createRequest1 = CreateExchangeRequest.newBuilder().apply { exchange = EXCHANGE }.build()

Switch to the builder used elsewhere instead of newBuilder.

[jcorilla]

Reviewable status: 4 of 5 files reviewed, 1 unresolved discussion (waiting on @tristanvuong2021)

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src/main/kotlin/org/wfanet/measurement/kingdom/service/internal/testing/ExchangesServiceTest.kt line 283 at r3 (raw file):

Previously, tristanvuong2021 (Tristan Vuong) wrote…

Switch to the builder used elsewhere instead of newBuilder.

Done.

[tristanvuong2021]

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[SanjayVas]

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[Marco-Premier]

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[jcorilla]

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