{ "example":
  { "type": ["@", "rules", "proto", "library"]
  , "name": ["example"]
  , "srcs": ["example.proto"]
  }
, "write":
  { "type": ["@", "rules", "CC", "binary"]
  , "name": ["write"]
  , "srcs": ["write.cc"]
  , "private-proto": ["example"]
  }
, "read":
  { "type": ["@", "rules", "CC", "binary"]
  , "name": ["read"]
  , "srcs": ["read.cc"]
  , "private-proto": ["example"]
  }
}