Even in 2016, China was already the leading infrastructure investor in the country. Long history of bigBrother/smallBrother brotherhood. Chinese companies have too much capacity and need to expand to SEAsia. These companies include exporters, real estate, casino, manufacturing, and retail shops targetting expat Chinese. They probably see Cambodia like a poor cousin of Guizhou. That was my impression of Cambodia even before OBOR.

After reading a a bit of political analysis of OBOR, I feel Cambodia has probably stronger dependency on China than other Asian countries.

* Cambodia government has probably the longest political alliance with China, which was tested repeatedly after the US-Vietnam war, and during international sanctions. Among the ASEAN countries, China often views Cambodia as its natural confidant and uses Cambodia to sway regional policy decisions.
* Cambodia is one of the least developed SEAsian nations and need infrastructure (OBOR) more than other nations.

As long as Chinese investments (OBOR etc) keep flowing, I think the Cambodia economy would grow at the current fast pace. Real estate sector is esp. sensitive to Chinese hot money. In a way, I am long OBOR -and- long Sino-Cambodia brotherhood. You can say I have placed big bets.

https://www.orfonline.org/research/china-relationship-asean-explainer/ says

One of the ASEAN countries closest to China is Cambodia, often accused of kowtowing to China. Its economic, military, educational and cultural relations with China are robust. It has deep penetration of BRI projects. It downplays the South China Sea issue within ASEAN forums. In many ways, Cambodia represents the dilemmas of a small insecure nation with an authoritarian regime in need of the backing of a great power to survive.

All politics is local, including Cambodia’s.