Fix handling of multiple responses in one read

[at-wat]

boost::asio::async_read_until may return multiple blocks of data (separated by specified delimiter) when they are received shortly.
Current implementation dropped second and later blocks.

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Found during #151 development

[codecov]

Codecov Report

Attention: Patch coverage is 75.60976% with 10 lines in your changes are missing coverage. Please review.

Project coverage is 80.31%. Comparing base (c27faaa) to head (d655009).

Files	Patch %	Lines
include/scip2/response/time_sync.h	20.00%	4 Missing ⚠️
test/src/test_scip2.cpp	83.33%	4 Missing ⚠️
include/scip2/response/reset.h	50.00%	1 Missing ⚠️
include/scip2/response/stream.h	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #152      +/-   ##
==========================================
+ Coverage   80.15%   80.31%   +0.16%     
==========================================
  Files          31       33       +2     
  Lines        1305     1326      +21     
==========================================
+ Hits         1046     1065      +19     
- Misses        259      261       +2     

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[at-wat]

Continued lines must be processed on the next callback

[sqbot]

[262] PASSED on noetic

All tests passed

build/test_results/urg_stamped/gtest-test_decode.xml: 4 tests
build/test_results/urg_stamped/gtest-test_device_time_origin.xml: 6 tests
build/test_results/urg_stamped/gtest-test_first_order_filter.xml: 6 tests
build/test_results/urg_stamped/gtest-test_param.xml: 12 tests
build/test_results/urg_stamped/gtest-test_scip2.xml: 2 tests
build/test_results/urg_stamped/gtest-test_timestamp_moving_average.xml: 6 tests
build/test_results/urg_stamped/gtest-test_timestamp_outlier_remover.xml: 4 tests
build/test_results/urg_stamped/gtest-test_walltime.xml: 4 tests
build/test_results/urg_stamped/roslint-urg_stamped.xml: 1 tests
build/test_results/urg_stamped/rostest-test_tests_e2e.xml: 1 tests
build/test_results/urg_stamped/rosunit-e2e.xml: 6 tests
Summary: 52 tests, 0 errors, 0 failures, 0 skipped

[nhatao]

Sorry for the late review.
I am concerned that the readUntilEnd() becomes a busy loop. Is it guaranteed that the readUntilEnd() will not be called while the lidar sends its measurement data continuously?

[at-wat]

@nhatao
All LIDAR responses including continuous measurement data are terminated by \n\n and the callback is registered by async_read_until(..., "\n\n"), readUntilEnd must always read until \n\n and return.

Even if the input buffer doesn't contains \n\n (by bug), std::getline will stop when the input buffer is entirely consumed.
(Input buffer won't be fed during callback as the next async_read_until is called after the callback)