add_call, add_drop methods #298

# to view logs

	name: CI

	on:
	push:
	branches: ["**"]
	pull_request:
	branches: ["**"]
	schedule:
	- cron: "0 6 * * 1-5"

	jobs:
	build:
	name: Build on ${{ matrix.os }}
	runs-on: ${{ matrix.os }}
	strategy:
	fail-fast: false
	matrix:
	os: [ubuntu-latest, macOS-latest]

	steps:
	- uses: actions/checkout@v2

	- name: install zenoh-cpp
	shell: bash
	run: \|
	mkdir -p build_install && cd build_install
	cmake ../install -DCMAKE_INSTALL_PREFIX=~/local
	cmake --install .

	- name: make examples
	shell: bash
	run: \|
	mkdir -p build && cd build
	cmake ..
	cmake --build . --target examples

	- name: make examples with zenoh-cpp as subbroject
	shell: bash
	run: \|
	mkdir -p build_examples_subproj && cd build_examples_subproj
	cmake ../examples -DCMAKE_BUILD_TYPE=Debug
	cmake --build . --config Debug

	- name: make examples with zenoh-cpp as installed package
	shell: bash
	run: \|
	mkdir -p build_examples_findproj && cd build_examples_findproj
	cmake ../examples -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=~/local -DZENOHCXX_SOURCE=PACKAGE
	cmake --build . --config Release

	- name: make tests
	shell: bash
	run: \|
	cd build
	cmake --build . --target tests



	- name: run tests
	shell: bash
	run: \|
	cd build
	ctest

	- name: Upload artifact
	uses: actions/upload-artifact@v2
	with:
	# Artifact name
	name: zenoh-cpp-${{ matrix.os }}
	# Directory containing files to upload
	path: \|
	target/release/examples

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