maximumConnections
Sets okhttp3.Dispatcher.maxRequestsPerHost for asynchronous SDK calls (.async { ... }). Under HTTP/1.1 this limits concurrent TCP sockets per host; under HTTP/2 it limits concurrent HTTP/2 streams multiplexed on a single connection.
Scope — important: this setting only throttles calls dispatched through OkHttp's async Dispatcher. Synchronous SDK calls (.sync()) bypass the dispatcher; consequently, neither the configured value nor the runtime fallback below applies to .sync() calls, even when an application invokes .sync() from multiple threads in parallel.
Public default: null — callers that inspect or copy this configuration will observe null. Runtime fallback: when null, the SDK does not override the dispatcher, so OkHttp's built-in maxRequestsPerHost of 5 applies to async calls only.
On HTTP/1.1, raising this opens more parallel sockets; on HTTP/2 (see origin for how to opt in), raising this allows more concurrent streams on a single connection.