はじめに OkHttp2とOkHttp3とでコネクションプールの部分が大きく変わっている。 Change Logからの引用。 There is no longer a global singleton connection pool. In OkHttp 2.x, all OkHttpClient instances shared a common connection pool by default. In OkHttp 3.x, each new OkHttpClient gets its own private connection pool. Applications should avoid creating many connection pools as doing so prevents connection reuse. Each connection pool hold
